Counter electrode for electrochromic devices

ABSTRACT

The embodiments herein relate to electrochromic stacks, electrochromic devices, and methods and apparatus for making such stacks and devices. In various embodiments, an anodically coloring layer in an electrochromic stack or device is fabricated to include a heterogeneous structure, for example a heterogeneous composition and/or morphology. Such heterogeneous anodically coloring layers can be used to better tune the properties of a device.

INCORPORATION BY REFERENCE

An Application Data Sheet is filed concurrently with this specificationas part of the present application. Each application that the presentapplication claims benefit of or priority to as identified in theconcurrently filed Application Data Sheet is incorporated by referenceherein in its entirety and for all purposes.

BACKGROUND

Electrochromism is a phenomenon in which a material exhibits areversible electrochemically-mediated change in an optical property whenplaced in a different electronic state, typically by being subjected toa voltage change. The optical property is typically one or more ofcolor, transmittance, absorbance, and reflectance. One well knownelectrochromic material, for example, is tungsten oxide (WO₃). Tungstenoxide is a cathodic electrochromic material in which a colorationtransition, transparent to blue, occurs by electrochemical reduction.

Electrochromic materials may be incorporated into, for example, windowsand mirrors. The color, transmittance, absorbance, and/or reflectance ofsuch windows and mirrors may be changed by inducing a change in theelectrochromic material. One well known application of electrochromicmaterials, for example, is the rear view mirror in some cars. In theseelectrochromic rear view mirrors, the reflectivity of the mirror changesat night so that the headlights of other vehicles are not distracting tothe driver.

While electrochromism was discovered in the 1960's, electrochromicdevices have historically suffered from various problems that haveprevented the technology from realizing its full commercial potential.

SUMMARY

The embodiments herein relate to electrochromic materials,electrochromic stacks, electrochromic devices, as well as methods andapparatus for making such materials, stacks, and devices. In variousembodiments, a counter electrode material may have a heterogeneouscomposition. In some cases, the counter electrode may be deposited toinclude multiple sublayers that may have different compositions and/ormorphologies. In these or other cases, the counter electrode may bedeposited to include a gradient in composition. The gradient (ifpresent) is typically in a direction that is normal to the plane of thecounter electrode. In various embodiments, the composition isheterogeneous with respect to the concentration of one or more metals inthe counter electrode material. The gradient in composition may extendover the entire thickness of the counter electrode or over only aportion (e.g., sublayer) of the counter electrode.

In one aspect of the disclosed embodiments, an electrochromic device isprovided, the electrochromic device including: a substrate; anelectrochromic layer disposed on or over the substrate, saidelectrochromic layer including a cathodically tinting electrochromicmaterial; and a counter electrode layer also disposed on or over thesubstrate, said counter electrode layer including (a) a first sublayerincluding a first anodically tinting material, and (b) a second sublayerincluding a second anodically tinting material, where the first andsecond anodically tinting materials have different compositions but eachinclude an oxide of at least one transition metal, and where the firstsublayer is disposed between the electrochromic layer and the secondsublayer.

In certain implementations, each of the first and second anodicallytinting materials may include the at least one transition metal andanother non-alkali metal. In some such implementations, the first andsecond anodically tinting materials may each include nickel andtungsten. The second anodically tinting material may further includetantalum. The second anodically tinting material may further includeniobium. The second anodically tinting material may further include tin.In some embodiments, the second anodically tinting material may includethe at least one transition metal, the other non-alkali metal, and asecond non-alkali metal, where the first anodically tinting materialcontains the at least one transition metal and the other non-alkalimetal as its only metals. In certain cases, the first and secondanodically tinting materials may each include the at least onetransition metal, the other non-alkali metal, and a second non-alkalimetal, where the second anodically tinting material has a higher atomicconcentration of the second non-alkali metal in comparison to the firstanodically tinting material.

The at least one transition metal may be selected from the groupconsisting of tungsten (W), tantalum (Ta), chromium (Cr), manganese(Mn), iron (Fe), cobalt (Co), nickel (Ni), rhodium (Rh), ruthenium (Ru),vanadium (V), iridium (Ir), and combinations thereof. The othernon-alkali metal may be selected from the group consisting of silver(Ag), aluminum (Al), arsenic (As), gold (Ag), boron (B), barium (Ba),beryllium (Be), bismuth (Bi), calcium (Ca), cadmium (Cd), cerium (Ce),cobalt (Co), chromium (Cr), copper (Cu), europium (Eu), iron (Fe),gallium (Ga), gadolinium (Gd), germanium (Ge), hafnium (Hf), mercury(Hg), indium (In), iridium (Ir), lanthanum (La), magnesium (Mg),manganese (Mn), molybdenum (Mo), niobium (Nb), neodymium (Nd), osmium(Os), protactinium (Pa), lead (Pb), palladium (Pd), praseodymium (Pr),promethium (Pm), polonium (Po), platinum (Pt), radium (Ra), rhenium(Re), rhodium (Rh), ruthenium (Ru), antimony (Sb), scandium (Sc),selenium (Se), silicon (Si), samarium (Sm), tin (Sn), strontium (Sr),tantalum (Ta), terbium (Tb), technetium (Tc), tellurium (Te), thorium(Th), titanium (Ti), thallium (Tl), uranium (U), vanadium (V), tungsten(W), yttrium (Y), zinc (Zn), zirconium (Zr), and combinations thereof.In certain embodiments, the other non-alkali metal may be selected fromthe group consisting of silver (Ag), arsenic (As), gold (Au), boron (B),cadmium (Cd), copper (Cu), europium (Eu), gallium (Ga), gadolinium (Gd),germanium (Ge), mercury (Hg), osmium (Os), lead (Pb), palladium (Pd),promethium (Pm), polonium (Po), platinum (Pt), radium (Ra), terbium(Tb), technetium (Tc), thorium (Th), thallium (Tl), and combinationsthereof. In some cases, the other non-alkali metal may be selected fromthe group consisting of tantalum (Ta), tin (Sn), and niobium (Nb). In aparticular example, the other non-alkali metal is tantalum (Ta). Inanother example, the other non-alkali metal is tin (Sn). In anotherexample, the other non-alkali metal is niobium (Nb).

In some embodiments, the first and second anodically tinting materialsmay each include a first transition metal, a second transition metal,and oxygen, where the ratio of the first transition metal to the secondtransition metal is different in the first and second anodically tintingmaterials. In these or other embodiments, the counter electrode layermay further include a third sublayer including a third anodicallytinting electrochromic material, where the first, second, and thirdanodically tinting materials have different compositions but eachinclude the at least one transition metal, and where the second sublayeris disposed between the first sublayer and the third sublayer. The firstanodically tinting material may include the at least one transitionmetal, a second transition metal, but no other transition metals, andoxygen; the second anodically tinting material may include the at leastone transition metal, the second transition metal, a third transitionmetal, and oxygen; and the third anodically tinting material may includethe at least one transition metal, the second metal, the thirdtransition metal, and oxygen, and the second and third anodicallytinting materials may have different concentrations of the thirdtransition metal. In certain implementations, the first and secondsublayers of the counter electrode layer may be in physical contact withone another. The first and second sublayers of the counter electrodelayer may be separated from one another by adefect-mitigating-insulating layer in some cases, thedefect-mitigating-insulating layer having an electronic resistivity ofbetween about 1 and 5×10¹⁰ Ohm-cm. In various embodiments, the firstanodically coloring material has a first affinity for lithium and thesecond anodically coloring material has a second affinity for lithium,where the first affinity for lithium and the second affinity for lithiummay be different.

The electrochromic device may have particular visual properties. In someembodiments, a transmitted b* value of the electrochromic device may beabout 14 or lower when the electrochromic device is in its cleareststate. For instance, a transmitted b* value of the electrochromic devicemay be about 10 or lower when the electrochromic device is in itsclearest state. The visible transmittance of the electrochromic devicemay be at least about 55% when the electrochromic device is in itsclearest state.

The counter electrode layer may have a particular overall thickness. Insome embodiments, the counter electrode layer may have an overallthickness between about 50 nm and about 650 nm, for example betweenabout 100 nm and about 400 nm, or between about 150 nm and about 300 nm.The first and second sublayers of the counter electrode layer may eachhave a morphology that is a mixture of amorphous and nanocrystallinephases with nanocrystallites having a diameter of less than about 50 nm.In certain cases, the second sublayer may be a defect-mitigatinginsulating layer having an electronic resistivity between about 1 and5×10¹⁰ Ohm-cm. The electrochromic device may further include atransparent conductive layer disposed on or over the electrochromiclayer and the counter electrode layer. The transparent conductive layermay include a doped indium oxide.

In some embodiments, at least one of the first and second anodicallytinting materials may include nickel, aluminum, and oxygen. In oneexample, the first anodically tinting material includes nickel,tungsten, and oxygen, and the second anodically tinting materialincludes nickel, aluminum, and oxygen. In certain embodiments, at leastone of the first and second anodically tinting materials includesnickel, silicon, and oxygen. For example, the first anodically tintingmaterial may include nickel, tungsten, and oxygen, and the secondanodically tinting material may include nickel, silicon, and oxygen.

In another aspect of the disclosed embodiments, an electrochromic deviceis provided, the electrochromic device including: a substrate; anelectrochromic layer disposed on or over the substrate, saidelectrochromic layer including a cathodically tinting electrochromicmaterial; and an anodically tinting counter electrode layer alsodisposed on or over the substrate, said counter electrode layerincluding (a) a first sublayer including a first nickel tungsten oxidecomposition, and (b) a second sublayer including a second nickeltungsten oxide composition, where the first and second nickel tungstenoxide compositions have different relative amounts of nickel and/ortungsten, and where the first sublayer is disposed between theelectrochromic layer and the second sublayer.

In certain implementations, the second nickel tungsten oxide compositionmay further include tantalum, niobium, tin, or a combination thereof. Inone example, the second nickel tungsten oxide composition includestantalum. In another example, the second nickel tungsten oxidecomposition includes niobium. In another example, the second nickeltungsten oxide composition includes tin. In a number of embodiments, thefirst nickel tungsten oxide composition may further include tantalum,where the second nickel tungsten oxide composition includes a greaterconcentration of tantalum than does the first nickel tungsten oxidecomposition. The first nickel tungsten oxide composition may furtherinclude niobium, and the second nickel tungsten oxide composition mayinclude a greater concentration of niobium than does the first nickeltungsten oxide composition. In some cases, the first nickel tungstenoxide composition may further includes tin, and the second nickeltungsten oxide composition may include a greater concentration of tinthan does the first nickel tungsten oxide composition.

The counter electrode layer may include a third sublayer. The thirdsublayer may include a third nickel tungsten oxide composition. Thefirst, second, and third nickel tungsten oxide compositions may havedifferent relative amounts of nickel and/or tungsten. The secondsublayer may be disposed between the first sublayer and the thirdsublayer. In some embodiments, the third nickel tungsten oxidecomposition may further include tantalum, niobium, tin, or a combinationthereof. In one example, the third nickel tungsten oxide compositionincludes tantalum. In another example, the third nickel tungsten oxidecomposition includes niobium. In another example, the third nickeltungsten oxide composition includes tin. In certain embodiments, thesecond and third nickel tungsten oxide compositions may each includetantalum, and the third nickel tungsten oxide composition may include agreater concentration of tantalum than does the second nickel tungstenoxide composition. In these or other embodiments, the second and thirdnickel tungsten oxide compositions may each include niobium, and thethird nickel tungsten oxide composition may include a greaterconcentration of niobium than does the second nickel tungsten oxidecomposition. In some cases, the second and third nickel tungsten oxidecompositions may each include tin, and the third nickel tungsten oxidecomposition may include a greater concentration of tin than does thesecond nickel tungsten oxide composition. In some embodiments, thecounter electrode layer may include a third sublayer including a thirdnickel tungsten oxide composition, where the second nickel tungstenoxide composition further includes metal M1, the third nickel tungstenoxide composition further includes metal M2, and where metals M1 and M2may be different from one another. In some such cases, the second nickeltungsten oxide composition may be substantially free of metal M2, andthe third nickel tungsten oxide composition may be substantially free ofmetal M1.

The first sublayer of the counter electrode layer may be a flash layerhaving a thickness of between about 10 nm and about 80 nm. In somecases, the thickness of the flash layer may be more limited, for examplebetween about 10 nm and about 50 nm, or between about 10 nm and about 30nm. The first sublayer may have a particular electronic resistivity, forexample between about 1 and 5×10¹⁰ Ohm-cm. In certain embodiments, eachof the first and second sublayers of the counter electrode layer mayhave a thickness between about 20 nm and about 200 nm. In some suchcases, the thickness of the first sublayer may differ from the thicknessof the second sublayer by between about 50 nm and about 200 nm.

In certain implementations, the second nickel tungsten oxide compositionmay include between about 2-10% atomic tantalum, and the third nickeltungsten oxide composition may include between about 5-20% atomictantalum. In certain embodiments, the first sublayer may substantiallyconsist of nickel tungsten oxide, the second sublayer may substantiallyconsist of nickel tungsten tantalum oxide that is between about 2-10%atomic tantalum, and the third sublayer may substantially consist ofnickel tungsten tantalum oxide that is between about 5-20% atomictantalum. For instance, the nickel tungsten tantalum oxide in the secondsublayer may be about 4% atomic tantalum, and the nickel tungstentantalum oxide in the third sublayer may be about 8% atomic tantalum. Inanother example, the second nickel tungsten oxide composition mayinclude between about 2-10% atomic niobium, and the third nickeltungsten oxide composition may include between about 5-20% atomicniobium. The first sublayer may substantially consist of nickel tungstenoxide, the second sublayer may substantially consist of nickel tungstenniobium oxide that is between about 2-10% atomic niobium, and the thirdsublayer may substantially consist of nickel tungsten niobium oxide thatis between about 5-20% atomic niobium. For example, the nickel tungstenniobium oxide in the second sublayer may be about 4% atomic niobium, andthe nickel tungsten niobium oxide in the third sublayer may be about 8%atomic niobium. In another embodiment, the second nickel tungsten oxidecomposition may include between about 2-10% atomic tin, and the thirdnickel tungsten oxide composition may include between about 5-20% atomictin. The first sublayer may substantially consist of nickel tungstenoxide, the second sublayer may substantially consist of nickel tungstentin oxide that is between about 2-10% atomic tin, and the third sublayermay substantially consist of nickel tungsten tin oxide that is betweenabout 5-20% atomic tin. For example, the nickel tungsten tin oxide inthe second sublayer may be about 4% atomic tin, and the nickel tungstentin oxide in the third sublayer may be about 8% atomic tin.

In various embodiments, the second nickel tungsten oxide composition mayfurther include a metal that is not present in the first nickel tungstenoxide composition. In certain implementations, at least one of the firstand second sublayers of the counter electrode layer may include a gradedcomposition. In a number of embodiments, the first and second sublayersof the counter electrode layer may each have a morphology that is amixture of amorphous and nanocrystalline phases with nanocrystalliteshaving a diameter of less than about 50 nm.

In a further aspect of the disclosed embodiments, a method offabricating an electrochromic device is provided, the method including:depositing an electrochromic layer including a cathodically coloringelectrochromic material; depositing a counter electrode layer by:depositing a first anodically tinting sublayer, and depositing a secondanodically tinting sublayer, where the first anodically tinting sublayeris positioned between the electrochromic layer and the second anodicallytinting sublayer, and where the first and second anodically tintingsublayers have different compositions and each include an oxide of atleast one transition metal.

In certain implementations, the second anodically tinting sublayer mayinclude one or more metals that are not present in the first sublayer.For instance, the second anodically tinting sublayer may includetantalum and the first anodically tinting sublayer may not includetantalum. In various embodiments the first anodically tinting sublayermay be substantially free of tantalum. In some examples, the secondanodically tinting sublayer may include niobium and the first anodicallytinting sublayer may not include niobium. In various embodiments thefirst anodically tinting sublayer may be substantially free of niobium.In certain implementations, the second anodically tinting sublayer mayinclude tin and the first anodically tinting sublayer may not includetin. In various embodiments the first anodically tinting sublayer may besubstantially free of tin. In some implementations, the secondanodically tinting sublayer may include aluminum and the firstanodically tinting sublayer may not include aluminum. The firstanodically tinting sublayer may be substantially free of aluminum. Inthese or other cases, the second anodically tinting sublayer may includesilicon and the first anodically tinting sublayer may not includesilicon. The first anodically tinting sublayer may be substantially freeof silicon.

In certain embodiments, depositing the counter electrode layer mayfurther include depositing a third anodically tinting sublayer includingan oxide of at least one transition metal, where the second anodicallytinting sublayer is positioned between the first and third anodicallytinting sublayers. In some such embodiments, the second and thirdanodically tinting sublayers may each include a metal that is notpresent in the first anodically tinting sublayer, and an atomicconcentration of the metal not present in the first anodically tintingsublayer may be higher in the third anodically tinting sublayer comparedto the second anodically tinting sublayer. For instance, the firstanodically tinting sublayer may substantially consist of nickel tungstenoxide, the second and third anodically tinting sublayers maysubstantially consist of nickel tungsten tantalum oxide, and theconcentration of tantalum may be higher in the third anodically tintingsublayer than in the second anodically tinting sublayer.

In some embodiments, different conditions may be used to depositdifferent sublayers. For instance, the first anodically tinting sublayermay be deposited at a higher rate of deposition than the secondanodically tinting sublayer. In these or other cases, the firstanodically tinting sublayer may be deposited at a lower sputter powerthan is used to deposit the second anodically tinting sublayer. In someembodiments, the first anodically tinting sublayer may be deposited at asputter power between about 5-20 kW/m², and the second sublayer may bedeposited at a sputter power between about 20-45 kW/m². In these orother implementations, a temperature of the partially fabricatedelectrochromic device may be lower during deposition of the firstanodically tinting sublayer than during deposition of the secondanodically tinting sublayer.

The method may also include lithiating one or more layers and/orsublayers. For instance, the method may further include lithiating thefirst anodically tinting sublayer before depositing the secondanodically tinting sublayer. In one embodiment, the method furtherincludes depositing lithium on the second anodically tinting sublayer,and then optionally depositing a third anodically tinting sublayer onthe second anodically tinting sublayer. In another embodiment, themethod further includes depositing a third anodically tinting sublayeron the second anodically tinting sublayer, and then depositing lithiumon the third anodically tinting sublayer.

In another aspect of the disclosed embodiments, a method of fabricatingan electrochromic device is provided, the method including: depositingan electrochromic layer including a cathodically coloring electrochromicmaterial; depositing a counter electrode layer by: depositing a firstanodically tinting sublayer, lithiating the first anodically tintingsublayer, and after lithiating the first anodically tinting sublayer,depositing a second anodically tinting sublayer, where the firstanodically tinting sublayer is positioned between the electrochromiclayer and the second anodically tinting sublayer, and where the firstand second anodically tinting sublayers have different compositions andeach include an oxide of at least one transition metal.

In a further aspect of the disclosed embodiments, an apparatus forfabricating an electrochromic device is provided, the apparatusincluding: (a) an integrated deposition system including: (i) a firstdeposition station including one or more first targets for depositing alayer of an electrochromic material on a substrate when the substrate ispositioned in the first deposition station, (ii) a second depositionstation containing one or more second targets for depositing a firstsublayer of a first counter electrode material on the substrate when thesubstrate is positioned in the second deposition station; (iii) a thirddeposition station containing one or more third targets for depositing asecond sublayer of a second counter electrode material on the substratewhen the substrate is positioned in the third deposition station, thesecond counter electrode material having a different composition thanthe first counter electrode material; and (b) a controller includingexecutable program instructions for passing the substrate through thefirst, second, and third deposition stations in a manner thatsequentially deposits a stack on the substrate, the stack including thelayer of electrochromic material, the first sublayer of the firstcounter electrode material, and the second sublayer of the secondcounter electrode material

In certain embodiments, the one or more second targets and the one ormore third targets may each include at least one pair of rotatablecylindrical targets. The controller may include executable instructionsto deposit the first counter electrode material at a lower sputter powerthan that used to deposit the second counter electrode material. In someembodiments, the controller may include executable instructions todeposit the first counter electrode material at a sputter power betweenabout 10-20 kW/m², and to deposit the second counter electrode materialat a sputter power between about 20-45 kW/m².

These and other features and advantages of the disclosed embodimentswill be described in further detail below, with reference to theassociated drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed description can be more fully understood whenconsidered in conjunction with the drawings in which:

FIG. 1 is a schematic cross-section of an electrochromic device inaccordance with certain embodiments.

FIG. 2 is a schematic cross-section of an electrochromic device wherethe counter electrode layer includes two sublayers according to certainembodiments.

FIG. 3 is a schematic cross-section of an electrochromic device wherethe counter electrode layer includes three sublayers according tocertain embodiments.

FIGS. 4A-4I show graphs illustrating the composition of one or morelayers in an electrochromic device according to various embodiments.

FIG. 5 depicts a method of fabricating an electrochromic stack which ispart of an electrochromic device according to certain embodiments.

FIG. 6A illustrates a rotating sputter target according to certainembodiments.

FIG. 6B shows a top-down view of two rotating sputter targets depositingmaterial on a substrate according to certain embodiments.

FIGS. 7A-7C relate to embodiments where a secondary sputter target isused to deposit material onto a primary sputter target, which thendeposits on a substrate according to certain embodiments.

FIG. 8 illustrates a hysteresis curve for depositing various opticallyswitchable materials.

FIGS. 9A-9E illustrate various embodiments of an integrated depositionsystem.

DETAILED DESCRIPTION Electrochromic Devices

A schematic cross-section of an electrochromic device 100 in accordancewith some embodiments is shown in FIG. 1. The electrochromic deviceincludes a substrate 102, a conductive layer (CL) 104, an electrochromiclayer (EC) 106 (sometimes also referred to as a cathodically coloringlayer or a cathodically tinting layer), an ion conducting layer (IC)108, a counter electrode layer (CE) 110, and a conductive layer (CL)114. The counter electrode layer 110 may be an anodicallycoloring/tinting layer and is sometimes referred to as an “ion storage”layer, because ions reside there when the electrochromic device is nottinted. Counter electrode layers are sometimes referred to herein asanodically coloring/tinting counter electrode layers, or even as ananodically coloring/tinting electrochromic layers. When counterelectrode layer 110 is described as an “electrochromic” layer, it isunderstood that the counter electrode layer tints when driven by ananodic potential, as ions are driven out of this layer andalternatively, becomes clear and substantially transparent when drivenby a cathodic potential as the ions are re-intercalated. Elements 104,106, 108, 110, and 114 are collectively referred to as an electrochromicstack 120. A voltage source 116 operable to apply an electric potentialacross the electrochromic stack 120 effects the transition of theelectrochromic device from, e.g., a clear state to a tinted state. Inother embodiments, the order of layers is reversed with respect to thesubstrate. That is, the layers are in the following order: substrate,conductive layer, counter electrode layer, ion conducting layer,electrochromic material layer, conductive layer. The conductive layersare generally transparent conductive layers, though in reflectivedevices a conductive layer may be reflective, such as a metal layer.

It should be understood that the reference to a transition between aclear state and tinted state is non-limiting and suggests only oneexample, among many, of an electrochromic transition that may beimplemented. Unless otherwise specified herein, whenever reference ismade to a clear-tinted transition, the corresponding device or processencompasses other optical state transitions such asnon-reflective-reflective, transparent-opaque, etc. Further the terms“clear” and “bleached” refer to an optically neutral state, e.g.,untinted, transparent or translucent. Still further, unless specifiedotherwise herein, the “color” or “tint” of an electrochromic transitionis not limited to any particular wavelength or range of wavelengths. Asunderstood by those of skill in the art, the choice of appropriateelectrochromic and counter electrode materials governs the relevantoptical transition. In various embodiments herein, a counter electrodeis deposited to include a heterogeneous composition and/or morphology.For instance, the counter electrode may include two or more sublayers insome cases, the sublayers having different compositions and/ormorphologies. In these or other cases, the entire counter electrode or asublayer of a counter electrode may include a gradient in composition.While FIG. 1 shows the counter electrode layer 110 as a simple layer, itshould be understood that various embodiments herein utilize a counterelectrode layer that is not homogeneous.

In certain embodiments, the electrochromic device reversibly cyclesbetween a clear state and a tinted state. In the clear state, apotential is applied to the electrochromic stack 120 such that availableions in the stack that can cause the electrochromic material 106 to bein the tinted state reside primarily in the counter electrode 110. Whenthe potential on the electrochromic stack is reversed, the ions aretransported across the ion conducting layer 108 to the electrochromicmaterial 106 and cause the material to enter the tinted state.

In certain embodiments, all of the materials making up electrochromicstack 120 are inorganic, solid (i.e., in the solid state), or bothinorganic and solid. Because organic materials tend to degrade overtime, inorganic materials offer the advantage of a reliableelectrochromic stack that can function for extended periods of time.Materials in the solid state also offer the advantage of not havingcontainment and leakage issues, as materials in the liquid state oftendo. Each of the layers in the electrochromic device is discussed indetail, below. It should be understood that any one or more of thelayers in the stack may contain some amount of organic material, but inmany implementations one or more of the layers contains little or noorganic matter. The same can be said for liquids that may be present inone or more layers in small amounts. It should also be understood thatsolid state material may be deposited or otherwise formed by processesemploying liquid components such as certain processes employing sol-gelsor chemical vapor deposition.

Referring again to FIG. 1, voltage source 116 is typically a low voltageelectrical source and may be configured to operate in conjunction withradiant and other environmental sensors. Voltage source 116 may also beconfigured to interface with an energy management system, such as acomputer system that controls the electrochromic device according tofactors such as the time of year, time of day, and measuredenvironmental conditions. Such an energy management system, inconjunction with large area electrochromic devices (i.e., anelectrochromic window), can dramatically lower the energy consumption ofa building.

Any material having suitable optical, electrical, thermal, andmechanical properties may be used as substrate 102. Such substratesinclude, for example, glass, plastic, and mirror materials. Suitableplastic substrates include, for example acrylic, polystyrene,polycarbonate, allyl diglycol carbonate, SAN (styrene acrylonitrilecopolymer), poly(4-methyl-1-pentene), polyester, polyamide, etc. If aplastic substrate is used, it may be barrier protected and abrasionprotected using a hard coat of, for example, a diamond-like protectioncoating, a silica/silicone anti-abrasion coating, or the like, such asis well known in the plastic glazing art. Suitable glasses includeeither clear or tinted soda lime glass, including soda lime float glass.The glass may be tempered or untempered. In some embodiments ofelectrochromic device 100 with glass, e.g., soda lime glass, used assubstrate 102, there is a sodium diffusion barrier layer (not shown)between substrate 102 and conductive layer 104 to prevent the diffusionof sodium ions from the glass into conductive layer 104. The substratemay also include alkali (e.g., sodium) free fusion glass, such asGorilla Glass™, Willow Glass™ and similar commercially availableproducts from Corning Incorporated of Corning, N.Y. If such alkali freesubstrates are used, then no diffusion barrier is necessary, thoughoptical tuning layers may be used between the substrate and theelectrochromic device, in order to optimize color and reflectanceproperties of e.g., the window.

In some embodiments, the optical transmittance (i.e., the ratio oftransmitted radiation or spectrum to incident radiation or spectrum) ofsubstrate 102 is about 40 to 95%, e.g., about 90-92%. The substrate maybe of any thickness, as long as it has suitable mechanical properties tosupport the electrochromic stack 120. While the substrate 102 may be ofany size, in some embodiments, it is about 0.01 mm to 10 mm thick, insome cases between about 3 mm to 9 mm thick.

In some embodiments, the substrate is architectural glass. Architecturalglass is glass that is used as a building material. Architectural glassis typically used in commercial buildings, but may also be used inresidential buildings, and typically, though not necessarily, separatesan indoor environment from an outdoor environment. In certainembodiments, architectural glass is at least 20 inches by 20 inches, andcan be much larger, e.g., as large as about 72 inches by 120 inches.Architectural glass is typically at least about 2 mm thick.Architectural glass that is less than about 3.2 mm thick cannot betempered. In some embodiments with architectural glass as the substrate,the substrate may still be tempered even after the electrochromic stackhas been fabricated on the substrate. In some embodiments witharchitectural glass as the substrate, the substrate is a soda lime glassfrom a tin float line.

On top of substrate 102 is conductive layer 104. In certain embodiments,one or both of the conductive layers 104 and 114 is inorganic and/orsolid. Conductive layers 104 and 114 may be made from a number ofdifferent materials, including conductive oxides, thin metalliccoatings, conductive metal nitrides, and composite conductors.Typically, conductive layers 104 and 114 are transparent at least in therange of wavelengths where electrochromism is exhibited by theelectrochromic layer. Transparent conductive oxides include metal oxidesand metal oxides doped with one or more metals. Examples of such metaloxides and doped metal oxides include indium oxide, indium tin oxide,doped indium oxide, tin oxide, doped tin oxide, zinc oxide, aluminumzinc oxide, doped zinc oxide, ruthenium oxide, doped ruthenium oxide andthe like.

Since oxides are often used for these layers, they are sometimesreferred to as “transparent conductive oxide” (TCO) layers. The functionof the conductive layers is to spread an electric potential provided byvoltage source 116 over surfaces of the electrochromic stack 120 tointerior regions of the stack, with very little ohmic potential drop.Further details and examples related to TCO layers are provided in U.S.patent application Ser. No. 12/645,111, filed Dec. 22, 2009, and titled“FABRICATION OF LOW DEFECTIVITY ELECTROCHROMIC DEVICES,” which is hereinincorporated by reference in its entirety

Overlaying conductive layer 104 is cathodically coloring layer 106 (alsoreferred to as electrochromic layer 106). In certain embodiments,electrochromic layer 106 is inorganic and/or solid, in typicalembodiments inorganic and solid. The electrochromic layer may containany one or more of a number of different cathodically coloringelectrochromic materials, including metal oxides. Such metal oxidesinclude tungsten oxide (WO₃), molybdenum oxide (MoO₃), niobium oxide(Nb₂O₅), titanium oxide (TiO₂), vanadium oxide (V₂O₅), tantalum oxide(Ta₂O₅), and the like. In some embodiments, the metal oxide is dopedwith one or more dopants such as lithium, sodium, potassium, molybdenum,vanadium, titanium, and/or other suitable metals or compounds containingmetals. Mixed oxides (e.g., W—Mo oxide, W—V oxide) are also used incertain embodiments. A cathodically coloring electrochromic layer 106comprising a metal oxide is capable of receiving ions transferred froman anodically coloring counter electrode layer 110. Further detailsrelated to cathodically coloring electrochromic layers are provided inU.S. patent application Ser. No. 12,645,111, incorporated by referenceabove.

Generally, in cathodically coloring electrochromic materials, thecolorization/tinting (or change in any optical property—e.g.,absorbance, reflectance, and transmittance) of the electrochromicmaterial is caused by reversible ion insertion into the material (e.g.,intercalation) and a corresponding injection of a charge balancingelectron. Typically some fraction of the ion responsible for the opticaltransition is irreversibly bound up in the electrochromic material. Asexplained below, some or all of the irreversibly bound ions are used tocompensate “blind charge” in the material. In most electrochromicmaterials, suitable ions include lithium ions (Li⁺) and hydrogen ions(W) (i.e., protons). In some cases, however, other ions will besuitable. These include, for example, deuterium ions (D⁺), sodium ions(Na⁺), potassium ions (K⁺), calcium ions (Ca⁺⁺), barium ions (Ba⁺⁺),strontium ions (Sr⁺⁺), and magnesium ions (Mg⁺⁺). In various embodimentsdescribed herein, lithium ions are used to produce the electrochromicphenomena. Intercalation of lithium ions into tungsten oxide (WO_(3−y)(0<y≤˜0.3)) causes the tungsten oxide to change from transparent (clearstate) to blue (tinted state).

Referring again to FIG. 1, in electrochromic stack 120, ion conductinglayer 108 overlays electrochromic layer 106. In certain embodiments,this ion conducting layer 108 is omitted during deposition of the layersin the stack, and the cathodically coloring electrochromic layer 106 isdeposited in direct physical contact with the anodically coloringcounter electrode layer 110. An interfacial region where thecathodically coloring electrochromic layer 106 meets the anodicallycoloring counter electrode layer 110 may form as a result of particularprocessing steps, thereby allowing the interfacial region to act as anion conducting layer in a finished device.

Ion conducting layer 108 serves as a medium through which ions aretransported (in the manner of an electrolyte) when the electrochromicdevice transforms between the clear state and the tinted state. Invarious cases, ion conducting layer 108 is highly conductive to therelevant ions for the electrochromic and the counter electrode layers,but has sufficiently low electron conductivity that negligible electrontransfer takes place during normal operation. A thin ion conductinglayer (also sometimes referred to as an ion conductor layer) with highionic conductivity permits fast ion conduction and hence fast switchingfor high performance electrochromic devices. In certain embodiments, theion conducting layer 108 is inorganic and/or solid. When fabricated froma material and in a manner that produces relatively few defects, the ionconductor layer can be made very thin to produce a high performancedevice. In various implementations, the ion conductor material has anionic conductivity of between about 10⁸ Siemens/cm or ohm⁻¹cm⁻¹ andabout 10⁹ Siemens/cm or ohm⁻¹cm⁻¹ and an electronic resistance of about10¹¹ ohms-cm.

In other embodiments, the ion conductor layer may be omitted. In suchembodiments, no separate ion conductor material is deposited whenforming an electrochromic stack for an electrochromic device. Instead,in these embodiments the cathodically coloring electrochromic materialmay be deposited in direct physical contact with the anodically coloringcounter electrode material. One or both of the anodically coloring andcathodically coloring materials may be deposited to include a portionthat is oxygen rich compared to the remaining portion of the material.

Typically, the oxygen rich portion is in contact with the other type oflayer. For instance, an electrochromic stack may include an anodicallycoloring material in contact with a cathodically coloring material,where the cathodically coloring material includes an oxygen-rich portionin direct physical contact with the anodically coloring material. Inanother example, an electrochromic stack includes an anodically coloringmaterial in contact with a cathodically coloring material, where theanodically coloring material includes an oxygen-rich portion in directphysical contact with the cathodically coloring material. In a furtherexample, both the anodically coloring material and the cathodicallycoloring material include an oxygen-rich portion, where the oxygen-richportion of the cathodically coloring material is in direct physicalcontact with the oxygen-rich portion of the anodically coloringmaterial.

The oxygen-rich portions of these layers may be provided as distinctsublayers (e.g., a cathodically or anodically coloring material includesan oxygen-rich sublayer and a less-oxygen-rich sublayer). Theoxygen-rich portion of the layers may also be provided in a graded layer(e.g., the cathodically or anodically coloring material may include agradient in oxygen concentration, the gradient being in a directionnormal to the surface of the layers). Embodiments where the ionconductor layer is omitted and the anodically coloring counter electrodematerial is in direct contact with the cathodically coloringelectrochromic material are further discussed in the following U.S.Patents, each of which is herein incorporated by reference in itsentirety: U.S. Pat. Nos. 8,300,298, and 8,764,950.

On top of ion conducting layer 108 (when present) is anodically coloringlayer 110 (also referred to as counter electrode layer 110). In variousembodiments here, the counter electrode layer is deposited to include aheterogeneous structure. The structure may be heterogeneous with respectto composition and/or morphology. Further details of the disclosedcounter electrode structures and compositions are provided below. Insome embodiments, counter electrode layer 110 is inorganic and/or solid.The counter electrode layer may comprise one or more of a number ofdifferent materials that are capable of serving as reservoirs of ionswhen the electrochromic device is in the clear state. During anelectrochromic transition initiated by, e.g., application of anappropriate electric potential, the anodically coloring counterelectrode layer transfers some or all of the ions it holds to thecathodically coloring electrochromic layer, changing the electrochromiclayer to the tinted state. Concurrently, the counter electrode layertints with the loss of ions.

In various embodiments, one or more defect mitigating insulating layers(DMILs) may be provided. Such DMILs may be provided between the layersdescribed in FIG. 1, or within such layers. In some particularembodiments a DMIL may be provided between sublayers of a counterelectrode layer, though DMILs can also be provided at alternative oradditional locations. DMILs can help minimize the risk of fabricatingdefective devices. In certain embodiments, the insulating layer has anelectronic resistivity of between about 1 and 5×10¹⁰ Ohm-cm. In certainembodiments, the insulating layer contains one or more of the followingmetal oxides: cerium oxide, titanium oxide, aluminum oxide, zinc oxide,tin oxide, silicon aluminum oxide, tungsten oxide, nickel tungstenoxide, tantalum oxide, and oxidized indium tin oxide. In certainembodiments, the insulating layer contains a nitride, carbide,oxynitride, or oxycarbide such as nitride, carbide, oxynitride, oroxycarbide analogs of the listed oxides. As an example, the insulatinglayer includes one or more of the following metal nitrides: titaniumnitride, aluminum nitride, silicon nitride, and tungsten nitride. Theinsulating layer may also contain a mixture or other combination ofoxide and nitride materials (e.g., a silicon oxynitride). DMILs arefurther described in U.S. Pat. No. 9,007,674, incorporated by referenceabove.

The electrochromic devices in embodiments herein are also scalable tosubstrates smaller or larger than architectural glass. An electrochromicstack can be deposited onto substrates that are a wide range of sizes,up to about 12 inches by 12 inches, or even 80 inches by 120 inches.

In some embodiments, electrochromic glass is integrated into aninsulating glass unit (IGU). An insulating glass unit consists ofmultiple glass panes assembled into a unit, generally with the intentionof maximizing the thermal insulating properties of a gas contained inthe space formed by the unit while at the same time providing clearvision through the unit. Insulating glass units incorporatingelectrochromic glass would be similar to insulating glass unitscurrently known in the art, except for electrical leads for connectingthe electrochromic glass to voltage source. Due to the highertemperatures (due to absorption of radiant energy by an electrochromicglass) that electrochromic insulating glass units may experience, morerobust sealants than those used in conventional insulating glass unitsmay be necessary. For example, stainless steel spacer bars, hightemperature polyisobutylene (PIB), new secondary sealants, foil coatedPIB tape for spacer bar seams, and the like. In certain cases theelectrochromic glass may be incorporated into a laminate; the laminatemay be a stand-alone construct or incorporated into an IGU as one of thepanes of the IGU.

Counter Electrode Layer

In a number of embodiments herein, the anodically coloring counterelectrode layer is heterogeneous in composition or a physical featuresuch as morphology. Such heterogeneous counter electrode layers mayexhibit improved color, switching behavior, lifetime, uniformity,process window, etc.

In certain embodiments, the counter electrode layer includes two or moresublayers, where the sublayers have different compositions and/ormorphologies. One or more of such sublayers may also have a gradedcomposition. The composition and/or morphology gradient may have anyform of transition including a linear transition, a sigmoidaltransition, a Gaussian transition, etc. A number of advantages can berealized by providing the counter electrode as two or more sublayers.For instance, the sublayers may be different materials that havecomplimentary properties. One material may promote better color qualitywhile another material promotes high quality, long lifetime switchingbehavior. The combination of materials may promote a high degree of filmquality and uniformity while at the same time achieving a high rate ofdeposition (and therefore throughput). Some of the approaches outlinedherein may also promote better control of the lithium distributionthroughout the electrochromic device, and in some cases may lead toimprovements in morphology in the counter electrode (e.g., highertransmission) and the overall reduction of defects in the electrochromicdevice. Another benefit that may result from various embodiments hereinis the availability of one or more intermediate states. Differences inelectrical potentials between various sublayers may allow for lithium toreside in discrete locations (e.g., within particular sublayers toparticular degrees), thereby enabling the electrochromic device toachieve intermediate tint states between e.g., a fully tinted device anda fully clear device. In some cases, intermediate states can be achievedby applying different voltages to the device. The inclusion of multiplesub-layers within the counter electrode layer may reduce or eliminatethe need to apply different voltages to achieve different intermediatetint states. These and other benefits of the disclosed embodiments arefurther described below.

In some cases, a counter electrode includes a first sublayer of a firstanodically coloring counter electrode material and one or moreadditional sublayers of a second anodically coloring counter electrodematerial. In various cases, the first sublayer of the CE layer may besituated closer to the cathodically coloring electrochromic materialthan the second (and optional additional) sublayer(s) of the CE layer.In some implementations, the first sublayer is a flash layer, which isgenerally characterized as a thin and often quickly deposited layertypically having a thickness of not greater than about 100 nm, invarious cases not greater than about 80 nm. A flash layer may be betweenabout 5 nm thick and about 100 nm thick, between about 10 nm thick andabout 80 nm thick, or between about 10 nm thick and about 50 nm thick,or about 10 nm and about 30 nm thick. In some other cases, a separateflash layer (which may be an anodically coloring counter electrodematerial) may be provided between the electrochromic layer and the firstsublayer of the counter electrode. In some embodiments, a flash layermay be provided between the second sublayer and the transparentconductor layer. A flash layer, if present, may or may not exhibitelectrochromic properties. In certain embodiments, a flash layer is madeof a counter electrode material that does not change color withremaining electrochromic/counter electrode layers (though this layer mayhave a composition that is very similar to other layers such as ananodically coloring layer). In some embodiments, the first sublayer,whether a flash layer or thicker than a flash layer, has a relativelyhigh electronic resistivity, for example between about 1 and5×10 Ohm-cm.

Generally speaking, the first and second anodically coloring counterelectrode materials may each, independently, be any anodically coloringcounter electrode material. The first and/or second counter electrodematerials may be binary metal oxides (e.g., oxides that include twometals in addition to lithium or other transported ion, NiWO being oneexample), ternary metal oxides (e.g., oxides that include three metals,NiWTaO being one example), or even more complex materials. In many casesthe materials also include lithium, which to a certain extent may bemobile within the device. Particular examples of anodically coloringcounter electrode materials are provided below. As used herein, the termmetal is intended to include metals and metalloids (e.g., B, Si, Ge, As,Sb, Te, and Po).

In some embodiments, the first anodically coloring material may includeat least one transition metal selected from the group consisting ofchromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni),rhodium (Rh), ruthenium (Ru), vanadium (V), and iridium (Ir). The firstanodically coloring material may include at least one or more additionalmetals (in many cases at least one non-alkali metal) in addition to oneor more of the transition metals just listed. The additional metal mayin some embodiments be selected from the group consisting of silver(Ag), aluminum (Al), arsenic (As), gold (Ag), barium (Ba), beryllium(Be), bismuth (Bi), calcium (Ca), cadmium (Cd), cerium (Ce), cobalt(Co), chromium (Cr), copper (Cu), europium (Eu), iron (Fe), gallium(Ga), gadolinium (Gd), germanium (Ge), hafnium (Hf), mercury (Hg),indium (In), iridium (Ir), lanthanum (La), magnesium (Mg), manganese(Mn), molybdenum (Mo), niobium (Nb), neodymium (Nd), osmium (Os),protactinium (Pa), lead (Pb), palladium (Pd), praseodymium (Pr),promethium (Pm), polonium (Po), platinum (Pt), radium (Ra), rhenium(Re), rhodium (Rh), ruthenium (Ru), antimony (Sb), scandium (Sc),selenium (Se), silicon (Si), samarium (Sm), tin (Sn), strontium (Sr),tantalum (Ta), terbium (Tb), technetium (Tc), tellurium (Te), thorium(Th), titanium (Ti), thallium (Tl), uranium (U), vanadium (V), tungsten(W), yttrium (Y), zinc (Zn), zirconium (Zr), and combinations thereof.

In these or other embodiments, the second anodically coloring materialmay be the first anodically coloring material doped or otherwisecombined with one or more additional elements. The additional element(s)may include at least one a non-alkali metal in various cases. In someembodiments, the one or more additional element is selected from thegroup consisting of: silver (Ag), aluminum (Al), arsenic (As), gold(Ag), barium (Ba), beryllium (Be), bismuth (Bi), calcium (Ca), cadmium(Cd), cerium (Ce), cobalt (Co), chromium (Cr), copper (Cu), europium(Eu), iron (Fe), gallium (Ga), gadolinium (Gd), germanium (Ge), hafnium(Hf), mercury (Hg), indium (In), iridium (Ir), lanthanum (La), magnesium(Mg), manganese (Mn), molybdenum (Mo), niobium (Nb), neodymium (Nd),osmium (Os), protactinium (Pa), lead (Pb), palladium (Pd), praseodymium(Pr), promethium (Pm), polonium (Po), platinum (Pt), radium (Ra),rhenium (Re), rhodium (Rh), ruthenium (Ru), antimony (Sb), scandium(Sc), selenium (Se), silicon (Si), samarium (Sm), tin (Sn), strontium(Sr), tantalum (Ta), terbium (Tb), technetium (Tc), tellurium (Te),thorium (Th), titanium (Ti), thallium (Tl), uranium (U), vanadium (V),tungsten (W), yttrium (Y), zinc (Zn), zirconium (Zr), and combinationsthereof. In certain embodiments, the additional element(s) may includeat least one element selected from the group consisting of tantalum,tin, niobium, zirconium, silicon, aluminum, and combinations thereof.While the additional element in the second anodically coloring materialmay be a dopant, this is not necessarily the case. In some compositions,the additional element forms a compound or salt with other elements ofthe material.

In a particular example, the first anodically coloring material is NiWO.In these or other examples, the second anodically coloring material maybe NiWO that is doped with or otherwise includes an additional metal(e.g., a non-alkali metal, a transition metal, a post-transition metal,or a metalloid in certain cases), with the additional metal beingselected from the list presented above, with one example material beingNiWTaO. Other examples for the second anodically coloring material wherethe first anodically coloring material is NiWO include, but are notlimited to, NiWSnO, NiWNbO, NiWZrO, NiWAlO, and NiWSiO. In some similarembodiments, the first anodically coloring material may be NiWO and thesecond anodically coloring material may be nickel oxide that is dopedwith or otherwise includes an additional metal (e.g., a non-alkalimetal, a transition metal, a post-transition metal, or a metalloid incertain cases), with the additional metal being selected from the listpresented above. Example materials for the second anodically coloringmaterial include, but are not limited to, NiTaO, NiSnO, NiNbO, NiZrO,NiAlO, NiSiO, and combinations thereof. In one example, the secondanodically coloring material may be selected from the group consistingof NiTaO, NiSnO, NiNbO, NiAlO, NiSiO, and combinations thereof. Inanother example, the second anodically coloring material may be selectedfrom the group consisting of NiAlO and NiSiO.

In some embodiments, the first and second anodically coloring materialscontain the same elements, but in different proportions. For example,both materials may contain Ni, W, and Ta, but two or three of theelements in present in different mass or atomic ratios. Examples belowfurther illustrate this option.

In some other embodiments, the first and second sublayers may be moresignificantly different from one another compositionally. For instance,the first and second sublayers (and any additional sublayers) may eachbe any anodically coloring material, regardless of the composition ofthe other sublayers. As noted, additional examples of anodicallycoloring materials are provided below.

The two or more sublayers may have different physical properties. Invarious cases, a material used in one or more of the sublayers is amaterial that would not perform well (e.g., would exhibit poor colorquality, poor lifetime performance, slow switching speed, slowdeposition rate, etc.) as a counter electrode material if providedwithout the accompanying sublayer(s).

FIG. 2 provides a cross sectional view of an electrochromic stack, asdeposited, according to one embodiment. The stack includes transparentconductive oxide layers 204 and 214. In contact with transparentconductive oxide layer 204 is a cathodically coloring electrochromiclayer 206. In contact with transparent conductive oxide layer 214 isanodically coloring counter electrode layer 210, which includes twosublayers 210 a and 210 b. The first sublayer 210 a of the counterelectrode is in contact with the electrochromic layer 206, and thesecond sublayer 210 b is in contact with the transparent conductiveoxide layer 214. In this embodiment, no separate ion conductor layer isdeposited (though an interfacial region serving as an ion conductorlayer may be formed in situ from this construct as described in moredetail herein).

The first and second sublayers 210 a and 210 b of the anodicallycoloring counter electrode layer 210 may have different compositionsand/or morphologies. In various examples, the second sublayer 210 bincludes at least one metal and/or metal oxide that is not present inthe first sublayer 210 a. In a particular example, the first sublayer210 a is NiWO and the second sublayer 210 b is NiWO doped or otherwisecombined with another metal (e.g., NiWTaO, NiWSnO, NiWNbO, NiWZrO,NiWAlO, NiWSiO, etc.). In another example, the first sublayer 210 a isNiWO and the second sublayer 210 b is nickel oxide (NiO) doped orotherwise combined with another metal (e.g., NiTaO, NiSnO, NiNbO, NiZrO,NiAlO, NiSiO, etc.). In another embodiment, the first and secondsublayers 210 a and 210 b include the same elements at differentrelative concentrations.

In some embodiments, the first sublayer 210 a is a flash layer. Flashlayers are typically thin layers (and as such they are typically, butnot necessarily, deposited relatively quickly). In some embodiments, afirst sublayer of an anodically coloring counter electrode is a flashlayer that is between about 5 nm thick and about 100 nm thick, betweenabout 10 nm thick and about 80 nm thick, between about 10 nm thick andabout 50 nm thick, or about 10 nm and about 30 nm thick.

The thickness of the flash layer (or other counter electrode sublayerthat is not deposited as a flash layer) may depend upon the materialschosen for the various sublayers. One consideration that may affect themaximum thickness of each sublayer is the color qualities of eachsublayer in comparison to the color qualities of the remainingsublayers. In a number of cases, the remaining sublayers will havesuperior color performance (e.g., a less yellow clear state) compared tothe first sublayer/flash layer. In a particular example, a NiWTaOsublayer has superior color performance compared to a NiWO sublayer(which may be deposited as a flash layer). As such, it is desirable fora NiWO sublayer to be relatively thin to achieve a desired overall colorperformance in the device, e.g., a thin flash layer of NiWO will haveless yellow color than a thicker NiWO layer.

One competing concern related to the thickness of each sublayer is therelative deposition rates of the materials in the sublayers. In a numberof embodiments, the first sublayer/flash layer may be a material thatdeposits at a higher deposition rate than the material of the remainingsublayers. Similarly, a first sublayer/flash layer may be deposited at alower power than the remaining sublayers. These factors make itadvantageous to use relatively thicker first sublayers, to therebyachieve a higher throughput and/or reduce the amount of power used.These concerns are balanced with those described above to selectappropriate sublayer thicknesses.

The remaining sublayer(s) may be thicker than the first sublayer 210 ain many embodiments. In certain embodiments where the counter electrodelayer 210 includes two sublayers such as 210 a and 210 b, the secondsublayer 210 b may be between about 20 nm and about 300 nm thick, forexample between about 150 nm and about 250 nm thick, or between about125 nm and about 200 nm thick.

In certain embodiments, the second sublayer 210 b is homogeneous withrespect to composition. FIG. 4A presents a graph showing theconcentration of various elements present in the first and secondsublayers 210 a and 210 b of FIG. 2 in a particular embodiment where thefirst sublayer is NiM1O and the second sublayer is compositionallyhomogeneous NiM1M2O. The first sublayer 210 a is labeled CE1 and thesecond sublayer 210 b is labeled CE2. In this example, the firstsublayer has a composition that is about 25% nickel, about 8% M1, andabout 66% oxygen, and the second sublayer has a composition that isabout 21% nickel, about 3% M1, about 68% oxygen, and about 8% M2. M2 maybe a metal in various embodiments.

In other embodiments, the second sublayer 210 b may include a gradedcomposition. The composition may be graded with respect to the relativeconcentration of a metal therein. For instance, in some cases the secondsublayer 210 b has a graded composition with respect to a metal that isnot present in the first sublayer. In one particular example, the firstsublayer is NiWO and the second sublayer is NiWTaO, where theconcentration of tantalum is graded throughout the second sublayer. Therelative concentrations of the remaining elements (excluding thetantalum) may be uniform throughout the second sublayer, or they mayalso change throughout this sublayer. In a particular example, theconcentration of oxygen may also be graded within the second sublayer210 b (and/or within the first sublayer 210 a).

FIG. 4B presents a graph showing the concentration of M2 present in thefirst and second sublayers 210 a and 210 b of FIG. 2 in a particularembodiment where the first sublayer is NiM1O and the second sublayer isa graded layer of NiM1M2O. As with FIG. 4A, the first sublayer 210 a islabeled CE1 and the second sublayer is labeled CE2. In this example, theconcentration of M2 increases across the thickness of the secondsublayer, to a value of about 15% (atomic) at the face of the secondsublayer furthest away from the EC layer. The other elements are omittedfrom the figure; though in one embodiment, they reflect the compositionssubstantially as described in relation to FIG. 4A or 4D, adjusted asappropriate to accommodate the changing M2 concentration. In certainembodiments the concentration of M2 decreases across the thickness ofthe second sublayer, that is, the concentration of M2 is highest at theface of the second sublayer nearest the EC layer and decreases, reachinga minimum concentration at the face of the second sublayer furthest awayfrom the EC layer. In yet another embodiment, the concentration of M2 ishighest at an intermediate region across the thickness of the secondsublayer, that is, the concentration of M2 is highest e.g., in thecenter of the second sublayer and decreases across the second sublayertoward both faces of the second sublayer. In this embodiment, theconcentration of M2 at the faces of the second sublayer are notnecessarily the same.

In certain embodiments, the first and second sublayers may havecompositions that are more different from one another. FIG. 4C presentsa graph showing the concentration of various elements present in thefirst and second sublayers 210 a and 210 b of FIG. 2 in an embodimentwhere the first sublayer is NiM1O and the second sublayer is NiM2O. In aparticular case, M1 is tungsten and M2 is vanadium, though other metalsand materials may also be used. While FIG. 4C shows the concentration ofoxygen and nickel remaining constant throughout both sublayers of thecounter electrode layer, this is not always the case. The particularcompositions described with respect to FIGS. 4A-4C are merely providedas examples and are not intended to be limiting. Different materials andconcentrations/compositions may also be used.

FIG. 3 shows an additional example of an electrochromic stack similar tothat shown in FIG. 2. The stack in FIG. 3 includes transparentconductive oxide layers 304 and 314, cathodically coloringelectrochromic layer 306, and anodically coloring counter electrodelayer 311. Here, counter electrode layer 311 is made of three sublayers311 a-c. The first sublayer 311 a may be a flash layer as describedabove with respect to the first sublayer 210 a of FIG. 2. Each of thesublayers 311 a-c may have a different composition. The second and thirdsublayers 311 b and 311 c may include the same elements at differentrelative concentrations in some embodiments. In another embodiment, allof the sublayers 311 a-c include the same elements at different relativeconcentrations. There may be an IC layer (not shown in FIG. 3) betweenthe electrochromic layer 306 and the counter electrode layers 311.

In one example, the first sublayer 311 a is a first anodically coloringcounter electrode material, and the second and third sublayers 311 b and311 c are a second anodically coloring counter electrode material (eachdeposited at a different composition). The composition of the second andthird sublayers 311 b and 311 c may be homogeneous within each sublayer.

FIG. 4D presents a graph showing the concentration of M2 present in thefirst, second, and third sublayers 311 a-c of FIG. 3 where the firstsublayer is NiM1O and the second and third sublayers are differentcompositions of homogeneous NiM1M2O. The first sublayer is labeled CE1,the second sublayer is labeled CE2, and the third sublayer is labeledCE3. The other elements (M1, Ni, and O) are omitted from FIG. 4D. In oneembodiment, these elements reflect the compositions substantially asdescribed in relation to FIG. 4A or 4C, adjusted as appropriate for thechanging concentration of M2. In a related embodiment, the concentrationof M2 may be lower in the third sublayer than in the second sublayer.

In other cases, the composition within one or more of the second andthird sublayers 311 b and 311 c may be graded, for example with respectto the concentration of a metal (in some cases a metal that is notpresent in the first sublayer 311 a). FIG. 4E presents a graph showingthe concentration of M2 present in the first, second, and thirdsublayers 311 a-c of FIG. 3 where the first sublayer (CE1) is NiM1O, thesecond sublayer (CE2) is NiM1M2O with a graded composition of M2, andthe third sublayer (CE3) is compositionally homogeneous NiM1M2O. Theother elements (M1, Ni, and O) are omitted from FIG. 4E. In oneembodiment, these elements reflect the compositions substantially asdescribed in relation to FIG. 4A or 4C, adjusted as appropriate toaccommodate the changing concentration of M2. In a related embodiment,the composition may be graded in the opposite direction. For example,the concentration of M2 may decrease throughout the second sublayerinstead of increasing (when moving from CE1 to CE3).

As noted, in some implementations the second anodically coloring counterelectrode material may be the first counter electrode material with anadditional metal. In a particular embodiment, the concentration of thisadditional metal is lower in the second sublayer 311 b and higher in thethird sublayer 311 c. In a particular example, the first sublayer 311 ais NiWO, the second sublayer 311 b is NiWTaO, the third sublayer 311 cis NiWTaO, and the concentration of tantalum is higher in the thirdsublayer 311 c than in the second sublayer 311 b. In a similar example,the first sublayer 311 a is NiWO, the second and third sublayers 311 band 311 c are NiWSnO, and the concentration of tin is higher in thethird sublayer 311 c than in the second sublayer 311 b. Numerousanodically coloring materials and combinations of materials can be used.In a different embodiment, the concentration of the additional metal maybe higher in the second sublayer than in the third sublayer. Thesetrends (increasing or decreasing concentration of the additional metal)may continue for any number of sublayers.

With reference to FIG. 2, in another example, the first sublayer 210 ais NiWO, and the second sublayer 210 b is NiAlO or NiWAlO. In anotherexample, the first sublayer 210 a is NiWO, and the second sublayer 210 bis NiSiO or NiWSiO. With reference to FIG. 3, in one example the firstsublayer 311 a is NiWO, the second sublayer 311 b is NiAlO, the thirdsublayer 311 c is NiAlO, and the concentration of aluminum is higher (orlower) in the third sublayer 311 c than in the second sublayer 311 b. Inanother example, the first sublayer 311 a is NiWO, the second sublayer311 b is NiSiO, the third sublayer 311 c is NiSiO, and the concentrationof silicon is higher (or lower) in the third sublayer 311 c than in thesecond sublayer 311 b. As noted above, the trends in the concentrationof the additional (or different) metal (e.g., aluminum or silicon inthese examples) may continue for any number of sublayers.

In some cases, the concentration (atomic %) of the additional metal inthe third sublayer 311 c is at least 1.2× the concentration of theadditional metal in the second sublayer 311 b. For instance, theconcentration of the additional metal in the third sublayer 311 c may beat least about 1.5×, or at least about 2×, or at least about 2.5× theconcentration of the additional metal in the second sublayer 311 b. Insome embodiments, more than one additional metal not present in thefirst sublayer 311 a may be provided in the second and/or thirdsublayers 311 b/311 c. In some particular embodiments, the thirdsublayer 311 c may include another additional material (e.g., a metal oranother element) that is not present in either the first or secondsublayers 311 a and 311 b.

Expanding on an example provided above, in one embodiment the firstsublayer 311 a may be NiWO (at any appropriate composition), the secondsublayer 311 b may be NiWTaO (having a composition that includes about7% (atomic) tantalum and any appropriate relative composition of nickel,tungsten, and oxygen), and the third sublayer 311 c may also be NiWTaO(having a composition that includes about 14% (atomic) tantalum and anyappropriate relative composition of nickel, tungsten, and oxygen). Thisexample is shown in FIG. 4D (where M1 is tungsten and M2 is tantalum).In a similar example, the tantalum and/or tungsten may be swapped for adifferent metal.

As mentioned, a number of different materials may be provided for thefirst sublayer. In various embodiments, the first sublayer is NiM1O.Where the first sublayer is NiM1O, it may be provided at any appropriatecomposition. In certain implementations, a NiM1O sublayer has acomposition of Ni_(x)M1_(y)O_(z), where 0.2<x<0.3, 0.02<y<0.1, and0.5<z<0.75. In a number of implementations, M1 is tungsten (W), thoughthe embodiments are not so limited. Where M1 is tungsten and the firstsublayer is NiWO, the NIWO may have a composition of Ni_(x)W_(y)O_(z),where 0.2<x<0.3, 0.05<y<0.1, and 0.6<z<0.7.

Likewise, a number of different materials may be provided for the second(and optional additional) sublayers. As noted, these sublayers willoften include the material of the first sublayer with an additionalmetal (M2) and/or metal oxide. Where the first sublayer includes NiM1Oand the second/additional sublayers include NiM1M2O, thesecond/additional sublayers may have a composition ofNi_(a)M1_(b)M2_(c)O_(d), where 0.2<a<0.3, 0.05<b<0.1, 0.01<c<0.1, and0.5<d<0.75. In a number of embodiments, the subscript c is lower insublayers positioned closer to the electrochromic layer and higher insublayers positioned farther from the electrochromic layer.

The thickness of the sublayers is generally determined by the overalldesired thickness of the CE layer and the number of sublayers that areused. The desired thickness of the CE layer overall is determined atleast in part by the desired charge capacity of the CE layer, andexample thicknesses are provided below. Where the counter electrodelayer is provided as three sublayers as shown in FIG. 3, the firstsublayer 311 a may be a relatively thin flash layer as described above.The second and third sublayers 311 b and 311 c may have any relativethickness. For instance, the second sublayer 311 b may be thinner,thicker, or about equally as thick as the third sublayer 311 c.

In some embodiments, additional sublayers may be provided. Theadditional sublayers may be homogeneous with respect to composition, orthey may be graded as described above. The trends described withrelation to the first, second, and third sublayers of FIGS. 2 and 3 mayalso hold true in throughout additional sublayers in various embodimentswhere such additional sublayers are provided. In one example, thecounter electrode is deposited to include four sublayers, where thefirst sublayer (positioned closest to the electrochromic layer) includesa first material (e.g., NiM1O) and the second, third, and fourthsublayers include a second material (e.g., NiM1M2O) that includes anadditional element (e.g., a metal) that is not present in the firstsublayer. The concentration of this additional element may be higher insublayers that are farther away from the electrochromic layer and lowerin sublayers that are closer to the electrochromic layer. As oneparticular example, the first sublayer (closest to the electrochromiclayer) is NiWO, the second sublayer is NiWTaO with 3% (atomic) Ta, thethird sublayer is NiWTaO with 7% (atomic) Ta, and the fourth sublayer(farthest from the electrochromic layer) is NiWTaO with 10% (atomic) Ta.

In still another embodiment, the counter electrode may be provided as asingle layer, but the composition of the counter electrode layer may begraded. The composition may be graded with respect to one or moreelements present in the material. In some embodiments, the counterelectrode has a graded composition with respect to one or more metals inthe material. In these or other embodiments, the counter electrode mayhave a graded composition with respect to one or more non-metals, forexample oxygen. FIG. 4F presents a graph showing the concentration of M2present in a counter electrode layer where the counter electrode isprovided as a single layer with a graded composition. In this example,the composition is graded with respect to a metal therein (M2). Theother elements (Ni, M1, O) are omitted from FIG. 4F. In one embodiment,these elements reflect the compositions substantially as described inrelation to FIG. 4A or 4C, adjusted as appropriate to accommodate thechanging M2 composition.

Without wishing to be bound by theory or mechanism of action, it isbelieved that the disclosed first sublayer may help protect the ionconducting layer and/or electrochromic layer from damage arising fromexcessive heating or other harsh condition during deposition of thecounter electrode layer. The first sublayer may be deposited underconditions that are milder than those used to deposit the remainingsublayers. For instance, in some embodiments, the first sublayer may bedeposited at a sputter power between about 5-20 kW/m², and the secondsublayer may be deposited at a sputter power between about 20-45 kW/m².In one particular example where the first sublayer is NiWO and thesecond sublayer is NiWTaO, the NiWTaO may be deposited using highersputtering power than the NiWO. This high power process, if performed todeposit directly on the ion conducting and/or electrochromic layer,might in some implementations degrade the ion conducting and/orelectrochromic layer, for example due to excessive heating and prematurecrystallization of the relevant materials, and/or due to loss of oxygenin the ion conducting and/or electrochromic layer. However, where a thinflash layer of NiWO is provided as a first sublayer, this NiWO layer canbe deposited under more gentle conditions. The NiWO sublayer may thenprotect the underlying ion conducting and/or electrochromic layer duringdeposition of subsequent NiWTaO sublayer(s). This protection may lead toa more reliable, better functioning electrochromic device.

In some embodiments, an electrochromic device includes a tungsten oxidebased electrode layer that is cathodically coloring; and a nickel oxidebased counter electrode layer that is anodically coloring; where thenickel oxide based counter electrode layer includes at least a firstsublayer and a second sublayer, each of the first and second sublayersof the counter electrode layer having the formulaLi_(a)NiW_(x)A_(y)O_(z), where: a is 1 to 10; x is 0 to 1; y is 0 to 1;and z is at least 1; and wherein a, x, y, z, and A are selectedindependently for each of the first and second sublayers of the counterelectrode layer.

In certain embodiments, y may be greater than 0 for at least one of thefirst and second sublayers of the counter electrode layer. In someexamples, y may be zero in the first sublayer of the counter electrodelayer and greater than zero in the second sublayer of the counterelectrode layer. In these or other embodiments, x may be greater than 0for at least one of the first and second sublayers of the counterelectrode layer. For instance, x may be greater than zero in the firstsublayer of the counter electrode layer and zero in the second sublayerof the counter electrode layer.

In various embodiments, the first and second sublayers have differentcompositions. For each of the first and second sublayers of the counterelectrode layer, A may be independently selected from the groupconsisting of silver (Ag), aluminum (Al), arsenic (As), gold (Ag), boron(B), barium (Ba), beryllium (Be), bismuth (Bi), calcium (Ca), cadmium(Cd), cerium (Ce), cobalt (Co), chromium (Cr), copper (Cu), europium(Eu), iron (Fe), gallium (Ga), gadolinium (Gd), germanium (Ge), hafnium(Hf), mercury (Hg), indium (In), iridium (Ir), lanthanum (La), magnesium(Mg), manganese (Mn), molybdenum (Mo), niobium (Nb), neodymium (Nd),osmium (Os), protactinium (Pa), lead (Pb), palladium (Pd), praseodymium(Pr), promethium (Pm), polonium (Po), platinum (Pt), radium (Ra),rhenium (Re), rhodium (Rh), ruthenium (Ru), antimony (Sb), scandium(Sc), selenium (Se), silicon (Si), samarium (Sm), tin (Sn), strontium(Sr), tantalum (Ta), terbium (Tb), technetium (Tc), tellurium (Te),thorium (Th), titanium (Ti), thallium (Tl), uranium (U), vanadium (V),tungsten (W), yttrium (Y), zinc (Zn), zirconium (Zr), and combinationsthereof. In a number of embodiments, A may be a first metal in the firstsublayer and a second metal in the second sublayer, the first metalbeing different from the second metal. In some implementations, y may bezero in the first sublayer such that the first sublayer is LiNiWO. Insome embodiments, A in the first and/or second sublayer of the counterelectrode layer may be selected from the group consisting of: Ta, Nb,Sn, Al, and Si. In these or other embodiments, A in each of the firstand second sublayers of the counter electrode layer may be selected fromthe group consisting of: Ta, Nb, Sn, Al, and Si, where A in the firstsublayer of the counter electrode layer is different from A in thesecond sublayer of the counter electrode layer. In some implementations,y may be between about 0.1-1 for at least one of the first and/or secondsublayers of the counter electrode layer. In a particular embodiment, ymay be between about 0.1-1 for each of the first and second sublayers ofthe counter electrode layer.

In some embodiments, the first sublayer of the counter electrode may beNiWO, and the second sublayer of the counter electrode may be a materialselected from the group consisting of NiWTaO, NiWNbO, NiWSnO, NiWAlO,NiWSiO, NiTaO, NiNbO, NiSnO, NiAlO, NiSiO, and combinations thereof. Incertain implementations, the second sublayer of the counter electrodemay be a material selected from the group consisting of NiWTaO, NiWNbO,NiWSnO, NiWAlO, NiWSiO, and combinations thereof. The second sublayer ofthe counter electrode may be a material selected from the groupconsisting of NiTaO, NiNbO, NiSnO, NiAlO, NiSiO, and combinationsthereof. In various implementations, the first and second sublayers ofthe counter electrode may each independently be selected from the groupconsisting of NiWO, NiWTaO, NiWNbO, NiWSnO, NiWAlO, NiWSiO, NiTaO,NiNbO, NiSnO, NiAlO, NiSiO, and combinations thereof, where the materialof the first sublayer is different from the material of the secondsublayer. In certain embodiments, the first and second sublayers of thecounter electrode may each independently be selected from the groupconsisting of NiWO, NiWTaO, NiWNbO, NiWSnO, NiWAlO, NiWSiO, andcombinations thereof, where the material of the first sublayer isdifferent from the material of the second sublayer. In some cases, thefirst and second sublayers of the counter electrode may eachindependently be selected from the group consisting of NiWO, NiTaO,NiNbO, NiSnO, NiAlO, NiSiO, and combinations thereof, where the materialof the first sublayer is different from the material of the secondsublayer.

The disclosed embodiments may also exhibit improved performance arisingfrom higher quality morphology and improved morphology control withinthe anodically coloring materials. As described herein, the counterelectrode materials may be crystalline, nanocrystalline, amorphous, orsome combination thereof. It is often desirable for the degree ofcrystallinity to be relatively low, and for any crystals present to berelatively small. By providing the counter electrode as two or moresublayers, one or more additional interfaces are introduced within thecounter electrode (e.g., interfaces where the sublayers contact oneanother). These interfaces can disrupt the formation of crystals, forexample due to renucleation and related grain growth effects. Sucheffects may act to prevent the crystals from growing larger and limitthe size of any crystals that form. This effect on morphology may leadto fabrication of devices with fewer voids or other defects.

Similarly, where the counter electrode is deposited as one or moresublayers, the sublayers can act to smooth out bumps/valleys/striationsin underlying layers. Where the counter electrode layer is deposited asa single homogeneous layer in a single step, bumps/valleys/striationspresent on underlying layers (which may originate from the substrate insome cases) are largely transferred to/through the counter electrodelayer. By contrast, by depositing the counter electrode layer in severalsteps (e.g., using multiple sublayers), the sublayers can promote asmoother surface because the bumps/valleys/striations are lesssubstantial with each additional layer that is deposited. By reducingthe transfer of such surface non-uniformities through the layers of thedevice, several benefits may be realized. For instance, hermeticity maybe improved, which results in improved moisture control. Relatedly,queue times during fabrication may be reduced, thereby improvingthroughput.

Without wishing to be bound by theory or mechanism of action, it is alsobelieved that the disclosed methods may be used to achieve improvedcontrol over the distribution of lithium within an electrochromicdevice. Different counter electrode materials exhibit differentaffinities for lithium, and therefore the choice of counter electrodematerial(s) affects how the lithium ions are distributed in anelectrochromic device. By selecting particular materials andcombinations of materials, the distribution of lithium within the devicecan be controlled. The distribution of lithium within the device may beparticularly important in devices that are fabricated without depositinga separate ion conducting layer. In such embodiments, the distributionof lithium throughout the device can affect whether or not an ionconducting/substantially electronically insulating region forms in theinterfacial region between the electrochromic and counter electrodelayers after the electrochromic stack is deposited and the stack isfurther processed. In certain embodiments, the sublayers of the counterelectrode include materials having different affinities for lithium. Forinstance, the material of the first sublayer may have a higher or loweraffinity for lithium compared to the material of the second (oradditional) sublayer(s) of the counter electrode.

Relatedly, the disclosed methods may be used to achieve improved controlover the total amount of lithium used to fabricate an electrochromicdevice. In various cases, lithium may be added during deposition of thecounter electrode layer. In some embodiments, lithium may be addedduring deposition of one or more sublayers of the counter electrode. Inthese or other embodiments, lithium may be added between depositions ofsubsequent sublayers of the counter electrode. By controlling thedistribution of lithium and the total amount of lithium within theelectrochromic device, device uniformity and appearance may be improved.

Another benefit that may arise with the disclosed techniques is improvedcolor and switching performance. As mentioned above, certain counterelectrode materials exhibit better performance in terms of color (e.g.,clearer clear states, more attractive tinted states, etc.), switchingspeed, lifetime, and other properties. However, certain materials thatpromote high quality results with respect to one property may havedrawbacks with respect to other properties. For instance, a materialthat is desirable because it exhibits a very transparent and uncoloredclear state may suffer problems related to slow switching speed and/orshort lifetime. By combining this material with another counterelectrode material (which may have its own problems such as a relativelymore yellow clear state), it is possible in various implementations toachieve a counter electrode with improved properties. The drawbacksrelated to one counter electrode material may be mitigated by propertiesof another counter electrode material.

For example, in a particular embodiment the first sublayer/flash layermay be made of a material that has acceptable (but not exceptional)color quality in the clear state, and the second sublayer (and optionaladditional sublayers) may be made of a material that has superior colorquality in the clear state (compared to the material of the flashlayer). The color quality may be evaluated based on a* and/or b* valuesof the material, with higher quality color generally corresponding to a*and b* values near zero and lower quality color generally correspondingto a* and b* values further from zero. In various embodiments, a* and/orb* values for the first and second sublayers (in their clearest states)may vary by at least about 6, or at least about 3. In these or othercases, a* and/or b* values of the first and second sublayers (in theirclearest states) may vary by about 10 or less.

In some cases the flash layer may be deposited at a relatively high rateusing a low sputter power, and the second sublayer may be deposited at arelatively lower rate using a higher sputter power. The first sublayermay help to fabricate the devices more quickly while also protecting theion conducting and/or electrochromic layer during formation of thecounter electrode (e.g., by preventing the ion conducting and/orelectrochromic layer from being exposed to high temperatures generatedduring the high sputter power deposition of the second sublayer), andthe second sublayer may help provide high quality color performance tothe device.

In some cases, the separation of the counter-electrode into multiplelayers could lead to improved reliability or reduced defectivity throughtuning of the film stress in the film. Film stress within the counterelectrode layer can improve or degrade the adhesion of subsequentlayers, which can impact the long-term reliability of the device as itexperiences changes in voltage, temperature, humidity, ambient light,etc. Changes in film stress can impact the apparent defectivity of thedevice as well. Particles present on the substrate before or duringdevice deposition can cause shorting between the electrode layers, whichresults in a local zone of decreased coloration. The appearance of theseshorts can be decreased using a Defect-Mitigation Layer (DMIL), and someembodiments of the DMIL require the manipulation of stress within thecounter-electrode to eject particles before the DMIL is applied. This isdescribed in U.S. patent application Ser. No. 13/763,505, filed Feb. 8,2013, and titled “DEFECT-MITIGATION LAYERS IN ELECTROCHROMIC DEVICES.” Amulti-layered counter electrode could incorporate a high stress initiallayer, which may cause particles to deform or eject, and a low-stressfinal layer can fill in any open area created by the ejected particles.

In some embodiments, the anodically coloring counter electrode layer (orone or more sublayers therein) is a material that includes nickel,tungsten, tantalum, and oxygen. The materials may be provided togetheras NiWTaO, at any appropriate composition (or combination/arrangement ofcompositions throughout the counter electrode). Nickel tungsten tantalumoxygen based materials are especially beneficial as an anodicallycoloring material because they may be particularly clear or colorneutral in the clear state. Many counter electrode materials areslightly tinted (colored) even in their clear states. For instance, NiWOgenerally has a slight yellow tint in the clear state. For aestheticreasons, it is beneficial in various cases that both the cathodicallycoloring and anodically coloring materials in an electrochromic deviceare very clear (transparent) and colorless when the device is in theclear state.

Further, some counter electrode materials exhibit good color qualities(i.e., are very clear in their clear state), but are unsuitable forcommercial use because the materials' ability to undergo rapid opticaltransitions fades over time. In other words, for these materials theduration of an optical transition increases with the age/use of thedevice. In this case, a newly fabricated window would exhibit higherswitching speeds than an identical window that has been in use for e.g.,six months. One example of an anodically coloring counter electrodematerial that shows good color quality but decreasing transition speedover time is nickel tantalum oxide (NiTaO). The inclusion of tungsten insuch a material has been shown to significantly reduce the decrease inswitching speed over time. As such, NiWTaO is a valuable candidate forone or more of the anodically coloring counter electrode material(s).

The NiWTaO may have various compositions when used as an anodicallycoloring material. In certain embodiments, particular balances may bemade between the various components of the NiWTaO. For instance, anatomic ratio of Ni:(W+Ta) in the material may fall between about 1.5:1and 3:1, for example between about 1.5:1 and 2.5:1, or between about 2:1and 2.5:1. In a particular example the atomic ratio of Ni:(W+Ta) isbetween about 2:1 and 3:1. The atomic ratio of Ni:(W+Ta) relates to theratio of (i) nickel atoms in the material to (ii) the sum of the numberof tungsten and tantalum atoms in the material.

The NiWTaO material may also have a particular atomic ratio of W:Ta. Incertain embodiments, the atomic ratio of W:Ta is between about 0.1:1 and6:1, for example between about 0.2:1 and 5:1, or between about 1:1 and3:1, or between about 1.5:1 and 2.5:1, or between about 1.5:1 and 2:1.In some cases the atomic ratio of W:Ta is between about 0.2:1 and 1:1,or between about 1:1 and 2:1, or between about 2:1 and 3:1, or betweenabout 3:1 and 4:1, or between about 4:1 and 5:1. In someimplementations, particular atomic ratios of Ni:(W+Ta) and W:Ta areused. All combinations of disclosed Ni:(W+Ta) compositions and disclosedW:Ta compositions are contemplated, though only certain combinations areexplicitly listed herein. For instance, the atomic ratio of Ni:(W+Ta)may be between about 1.5:1 and 3:1, where the atomic ratio of W:Ta isbetween about 1.5:1 and 3:1. In another example, the atomic ratio ofNi:(W+Ta) may be between about 1.5:1 and 2.5:1, where the atomic ratioof W:Ta is between about 1.5:1 and 2.5:1. In a further example, theatomic ratio of Ni:(W+Ta) may be between about 2:1 and 2.5:1, where theatomic ratio of W:Ta is between about 1.5:1 and 2:1, or between about0.2:1 and 1:1, or between about 1:1 and 2:1, or between about 4:1 and5:1.

Other example materials for the counter electrode include, but are notlimited to, nickel oxide, nickel tungsten oxide, nickel vanadium oxide,nickel chromium oxide, nickel aluminum oxide, nickel manganese oxide,nickel magnesium oxide, chromium oxide, iron oxide, cobalt oxide,rhodium oxide, iridium oxide, manganese oxide, Prussian blue. Thematerials (e.g., metal and oxygen) may be provided at differentstoichiometric ratios as appropriate for a given application. In someother implementations, the counter electrode material may include ceriumtitanium oxide, cerium zirconium oxide, nickel oxide, nickel-tungstenoxide, vanadium oxide, and mixtures of oxides (e.g., a mixture of Ni₂O₃and WO₃). Doped formulations of these oxides may also be used, withdopants including, e.g., tantalum and tungsten and the other elementslisted above.

Because anodically coloring counter electrode layer contains the ionsused to produce the electrochromic phenomenon in the cathodicallycoloring electrochromic material when the cathodically coloringelectrochromic material is in the clear state, the anodically coloringcounter electrode may have high transmittance and a neutral color whenit holds significant quantities of these ions.

When charge is removed from an anodically coloring counter electrode(i.e., ions are transported from the counter electrode to theelectrochromic layer), the counter electrode layer will turn from a(more or less) transparent state to a tinted state.

The morphology of the counter electrode layer or any one or moresublayers therein may be crystalline, amorphous, or some mixturethereof. Crystalline phases may be nanocrystalline. In some embodiments,the counter electrode material layer (or one or more sublayers therein)is amorphous or substantially amorphous. Various substantially amorphouscounter electrodes have been found to perform better, under someconditions, in comparison to their crystalline counterparts. Theamorphous state of one or more counter electrode oxide material(s) maybe obtained through the use of certain processing conditions, describedbelow. While not wishing to be bound to any theory or mechanism, it isbelieved that amorphous counter electrode materials such asnickel-tungsten oxide or nickel-tungsten-tantalum oxide are produced byrelatively low energy atoms in the sputtering process. Low energy atomsare obtained, for example, in a sputtering process with lower targetpowers, higher chamber pressures (i.e., lower vacuum), and/or largersource to substrate distances. Amorphous films are also more likely toform where there is a relatively higher fraction/concentration of heavyatoms (e.g., W). Under the described process conditions films withbetter stability under UV/heat exposure are produced. Substantiallyamorphous materials may have some crystalline, typically but notnecessarily nanocrystalline, material dispersed in the amorphous matrix.The grain size and amounts of such crystalline materials are describedin more detail below.

In some embodiments, the morphology of the counter electrode or anysublayers therein may include microcrystalline, nanocrystalline and/oramorphous phases. For example, the counter electrode may be, e.g., amaterial with an amorphous matrix having nanocrystals distributedthroughout. In certain embodiments, the nanocrystals constitute about50% or less of the counter electrode material, about 40% or less of thecounter electrode material, about 30% or less of the counter electrodematerial, about 20% or less of the counter electrode material or about10% or less of the counter electrode material (by weight or by volumedepending on the embodiment). In certain embodiments, the nanocrystalshave a maximum diameter of less than about 50 nm, in some cases lessthan about 25 nm, less than about 10 nm, or less than about 5 nm. Insome cases, the nanocrystals have a mean diameter of about 50 nm orless, or about 10 nm or less, or about 5 nm or less (e.g., about 1-10nm).

In certain embodiments, it is desirable to have a nanocrystal sizedistribution where at least about 50% of the nanocrystals have adiameter within 1 standard deviation of the mean nanocrystal diameter,for example where at least about 75% of the nanocrystals have a diameterwithin 1 standard deviation of the mean nanocrystal diameter or where atleast about 90% of the nanocrystals have a diameter within 1 standarddeviation of the mean nanocrystal diameter.

It has been found that counter electrode materials that include anamorphous matrix tend to operate more efficiently compared to counterelectrode materials that are relatively more crystalline. In certainembodiments, one material/additive may form a host matrix in whichdomains of the base anodically coloring material may be found. Invarious cases, the host matrix is substantially amorphous. In certainembodiments, the only crystalline structures in the counter electrodeare formed from a base anodically coloring electrochromic material in,e.g., oxide form. One example of a base anodically coloringelectrochromic material in oxide form is nickel tungsten oxide.Additives may contribute to forming an amorphous host matrix that is notsubstantially crystalline, but which incorporates domains (e.g.,nanocrystals in some cases) of the base anodically coloringelectrochromic material. One example additive is tantalum. In otherembodiments, the additive and the anodically coloring base materialtogether form a chemical compound with covalent and/or ionic bonding.The compound may be crystalline, amorphous, or a combination thereof. Inother embodiments, the anodically coloring base material forms a hostmatrix in which domains of the additive exist as discrete phases orpockets. For example certain embodiments include an amorphous counterelectrode having an amorphous matrix of a first material, with a secondmaterial, also amorphous, distributed throughout the first material inpockets, for example, pockets of the diameters described herein forcrystalline materials distributed throughout an amorphous matrix.

In various embodiments, sublayers within a counter electrode layer mayhave different degrees of crystallinity. For instance, the firstsublayer may be more crystalline, less crystalline, or about equally ascrystalline as the second (or additional) sublayers of the counterelectrode. For instance, the first sublayer may have larger, smaller, orabout equal average crystal size as the second (or additional)sublayers. The first sublayer may also have a greater, lesser, or aboutequal proportion of material that is crystalline, compared to the second(or additional) sublayers.

In some embodiments, the thickness of the counter electrode is about 50nm to about 650 nm. In some embodiments, the thickness of the counterelectrode is about 100 nm to about 400 nm, sometimes in the range ofabout 150 nm to 300 nm, or between about 200 nm to 300 nm. The thicknessof the counter electrode layer is also substantially uniform. In oneembodiment, a substantially uniform counter electrode layer varies onlyabout ±10% in each of the aforementioned thickness ranges. In anotherembodiment, a substantially uniform counter electrode layer varies onlyabout ±5% in each of the aforementioned thickness ranges. In anotherembodiment, a substantially uniform counter electrode layer varies onlyabout ±3% in each of the aforementioned thickness ranges.

The amount of ions held in the counter electrode layer during the clearstate (and correspondingly in the electrochromic layer during the tintedstate) and available to drive the electrochromic transition depends onthe composition of the layers as well as the thickness of the layers andthe fabrication method. Both the electrochromic layer and the counterelectrode layer are capable of supporting available charge (in the formof lithium ions and electrons) in the neighborhood of several tens ofmillicoulombs per square centimeter of layer surface area. The chargecapacity of an electrochromic film is the amount of charge that can beloaded and unloaded reversibly per unit area and unit thickness of thefilm by applying an external voltage or potential. In one embodiment,the WO₃ layer has a charge capacity of between about 30 and about 150mC/cm²/micron. In another embodiment, the WO₃ layer has a chargecapacity of between about 50 and about 100 mC/cm²/micron. In oneembodiment, the counter electrode layer has a charge capacity of betweenabout 75 and about 200 mC/cm²/micron. In another embodiment, the counterelectrode layer has a charge capacity of between about 100 and about 150mC/cm²/micron.

The counter electrode layer and/or the electrochromic device may haveparticular properties when considering all the layers/sublayers therein.For instance, in some embodiments a counter electrode will have a b*value that is between about 2-10, or between about 4-6, when the counterelectrode is in its clearest state (when the counter electrode is heldat its most cathodic potential and the ions fully reside in the counterelectrode layer of the device). An electrochromic device fabricatedaccording to the disclosed embodiment may have a b* value that isbetween about 6-14, or between about 9-12, when the device is in itsclearest state. These values take into account color that may resultfrom both the counter electrode layer as well as the electrochromiclayer. An electrochromic window that is fabricated according to thedisclosed techniques may have a b* value that is between about 6-14, orbetween about 9-12, when the electrochromic window is in its cleareststate. Such a window's b* value may be less than 10. In various cases,an electrochromic device and/or electrochromic window according to thedisclosed embodiments may have a transmitted b* value of about 14 orbelow, 12 or below, or 10 or below, when the device or window is in itsclearest state. These values take into account color that may resultfrom the counter electrode layer, the electrochromic layer, thesubstrates (e.g., glass, etc.), the conducting oxide layers, and anyother layers present in the window.

Similarly, the counter electrode layer and/or the electrochromic devicemay have a particular transmissivity when in its clearest state. In someembodiments, a counter electrode layer will have a visible transmittanceof at least about 65% when in its clearest state. An electrochromicdevice as disclosed herein may have a visible transmittance of at leastabout 55% when in its clearest state. An electrochromic windowfabricated as disclosed herein may have a visible transmittance of atleast about 50% when in its clearest state.

In certain embodiments, an electrochromic layer may be implemented astwo or more sub-layers, as described in relation to the counterelectrode layer. Details related to differences between the sub-layers,as well as details related to changes within a layer, may also apply toan electrochromic layer (instead of, or in addition to, a counterelectrode layer).

Other Aspects Related to Varied Compositions within EC Devices

Much of the discussion above has focused on embodiments that include acounter electrode layer that has a heterogeneous composition. Often, thecomposition of the counter electrode is heterogeneous with respect to ametal therein. Alternatively or in addition, the counter electrode (oranother layer/region in the electrochromic device) may be fabricated toinclude a heterogeneous composition with respect to another element suchas oxygen. In various embodiments, for instance, the electrochromicand/or counter electrode layers may be deposited to include anoxygen-rich portion. The oxygen-rich portion (in some cases this portionis provided as a distinct sublayer, while in other cases a distinctsublayer is not provided) may be in contact with the other electrodelayer (e.g., an oxygen-rich portion of an electrochromic layer may bedeposited in direct contact with the counter electrode layer, and/or anoxygen-rich portion of a counter electrode layer may be deposited indirect contact with the electrochromic layer). The heterogeneousstructure of the electrochromic and/or counter electrode layer maypromote formation of an interfacial region between these two layers,where (upon further processing) the interfacial region acts as a regionthat is ion conducting and substantially electronically insulating. Theinterfacial region itself may be heterogeneous with respect tocomposition and/or morphology.

Generally speaking, in certain embodiments the interfacial region mayhave a heterogeneous structure that includes at least two discretecomponents represented by different phases and/or compositions. Further,the interfacial region may include a gradient in these two or morediscrete components such as an ion conducting material and anelectrochromic material (for example, a mixture of lithium tungstate andtungsten oxide). The gradient may provide, for example, a variablecomposition, microstructure, resistivity, dopant concentration (forexample, oxygen concentration), stoichiometry, density, and/or grainsize regime. The gradient may have many different forms of transitionincluding a linear transition, a sigmoidal transition, a Gaussiantransition, etc.

Because the interfacial region may be formed from a portion of theelectrochromic and/or counter electrode layers, these layers may also bedeposited to include such heterogeneous structures.

In certain implementations, the electrochromic stack may be provided asa graded electrochromic element. An EC element has no abrupt transitionbetween an EC layer and an IC layer or between an IC layer and a CElayer, but rather is a single layer graded composition having an ECregion, which transitions to an IC region (the interfacial region),which transitions to a CE region. Since an EC element is a single layerof graded composition, EC elements can be described in a number of waysincluding those below. The following description is meant toillustrative of certain embodiments of EC elements.

One embodiment is an EC element which is a single layer gradedcomposition including an EC region, an IC region and a CE region,respectively. In one embodiment, the EC element is all solid-state andinorganic. A single EC element can be described in a number of ways inorder to understand the graded composition of which it is comprised. Invarious embodiments, the single layer graded composition EC element hasno abrupt boundaries between EC/IC or between IC/CE. Rather both ofthese interfaces are characterized by graded compositions as discussedherein. In some cases, the single layer graded composition EC elementhas a continuously variable composition across all regions of theelement. In other cases, the element has at least one region, or atleast two regions, of constant composition. FIGS. 4G-4I are examples ofhow one can metric the composition of one type of EC element. In theseparticular examples, the EC element's EC region includes a firsttransition metal; the IC region includes an alkali metal, and the CEregion comprises a mixed transition metal oxide. The IC region may beformed after the EC and CE regions are deposited in contact with oneanother. In a particular example, the mixed transition metal oxideincludes the first transition metal and an additional transition metal,although in other examples, the mixed transition metal oxide does notinclude the first transition metal. In some devices, FIGS. 4G-4I aredescribing the same EC element, but in different ways. Each of theseways exemplify how one might describe any number of EC elements inaccord with embodiments described herein. In this example, some of thecomponents depicted in the graphs are present throughout the gradedcomposition, some are not. For example, one transition metal iscontinuously present in significant concentration across the entiredevice, from the EC region, through the CE region. The invention is notlimited in this way. In some embodiments some or all the components arepresent at least in some de minimus amount (or even a significantamount) throughout the EC element. In certain examples within the realmof FIGS. 4G-4I, each component has at least some presence in each regionof the EC element.

Referring to FIG. 4G, the EC element is described in terms of the molefraction of elemental components from which it is composed as a functionof the region, EC, IC or CE in which the components occur. Starting fromthe origin and moving from left to right across the graph, in the ECregion, there is a higher mole fraction of oxygen (O) than the firsttransition metal (TM₁). For example, this could represent tungsten oxidein approximately a 3:1 ratio of oxygen to tungsten. Moving further tothe right, the mole fraction of the first transition metal declinesstarting somewhere in the EC region. At some point in the CE region, themole fraction of oxygen and the first transition metal level off. Forexample, this could represent nickel tungsten oxide of stablecomposition in the CE region. In this example, a second transition metal(TM₂) is present throughout the EC element, in this particular examplehaving a higher mole fraction in the CE region than the other regions ofthe EC element. Also, an alkali metal (M_(alk)) is present in the ECelement. For the purposes of this description, “alkali metal” is meantto encompass both neutral elemental alkali metal and cations thereof,e.g., bound in a material matrix or unbound and thus able tointercalate/transport during device operation. In this example thealkali metal has the highest mole fraction in the IC region. This mightcorrespond to lithium of lithium tungstate existing in this region inone example. The oxygen concentration may also be highest in the ICregion, as shown in FIG. 4G. This high oxygen concentration may be theresult of depositing the materials in the IC region to besuperstoichiometric with respect to oxygen. In certain embodiments, thematerial of the IC region may include a superstoichiometric (withrespect to oxygen) form of the material in the EC region and/or CEregion. It is important to note that the mole fraction of componentsdepicted in FIG. 4G are those components fixed in the EC element, e.g.,the alkali metal component does not include mobile lithium ions thatmight be used to drive the EC element to color or bleach (as such ionsare mobile and their position in the EC element will change dependingupon an applied charge, for example). This example is illustrative ofhow one might describe the composition of an EC element.

One embodiment is an EC element including: a) a first transition metalhaving a higher mole fraction of the composition in the EC region than asecond transition metal, if present, in the EC region, b) an alkalimetal having a maximum mole fraction of the composition in the IC regionas compared to the EC region and the CE region; and c) the secondtransition metal having its maximum mole fraction, of the composition ofany region of the EC element, in the CE region.

Referring to FIG. 4H, if one were to consider the composition of thesame EC element as described in relation to FIG. 4G, but withoutconsidering oxygen content, that is another way to describe embodimentsdescribed herein. For example, in this graph the y-axis is not molefraction, but rather metal concentration; that is, the concentration ofeach metal, TM₁, M_(alk), and TM₂, in each region of the gradedcomposition. In this example, each of the first transition metal and thealkali metal are described in terms of their concentration relative tothe other two metals. The second transition metal is described in termsof its absolute concentration. Referring to FIG. 4H, in the EC region,the first transition metal has its maximum concentration, relative tothe other metals. The alkali metal has its maximum concentration in theIC region, relative to the other metals. The second transition metal hasits maximum (absolute) concentration in the CE region. In this example,TM₁ and TM₂ have substantially the same concentration in the CE region,e.g., this might represent NiWO.

One embodiment is an EC element, including: a) a first transition metalhaving a maximum concentration, relative to other metals in the ECelement, in the EC region, b) an alkali metal having a maximumconcentration, relative to other metals in the EC element, in the ICregion, and c) a second transition metal having its absolute maximumconcentration in the CE region of the EC element.

FIG. 4I describes the composition of the same EC element as described inrelation to FIGS. 4G and 4H, but looking at the actual composition,e.g., compounds, that make up each region. For example, in this graphthe y-axis is % composition of each compound, oxide of the firsttransition metal (TM₁-oxide), an oxide mixture which includes the alkalimetal, along with the first and second transition metals(M_(alk)-TM₁-TM₂ oxide mixture) and a mixed transition metal oxide(TM₁-TM₂ oxide), in each region of the graded composition. As mentionedthe mixed transition metal oxide need not include the first transitionmetal (e.g., it can include a second and third transition metal), but itdoes in this example. In this example, the TM₁-oxide is most abundant inthe EC region, and it is the primary constituent of the EC region. TheM_(alk)-TM₁-TM₂ oxide mixture is the primary constituent of the ICregion and the TM₁-TM₂ oxide is the primary constituent of the CEregion. Note that the M_(alk)-TM₁-TM₂ oxide mixture may include morethan one compound in a matrix of materials, e.g., this could represent agraded mixture of lithium tungstate, tungsten oxide and nickel tungstenoxide. The morphology of the EC element may vary across the layer, i.e.the graded region may have amorphous portions, crystalline portionsand/or mixed amorphous crystalline portions in any one or more of theregions. In some embodiments, the CE region is substantially amorphous.

One embodiment is an EC element, including: a) a first transition metaloxide which is the primary constituent of the EC region, b) a mixedtransition metal oxide which is the primary constituent of the CEregion, and c) a mixture including the first transition metal and themixed transition metal oxide, the mixture being the primary constituentof the IC region. One embodiment is an EC element, including: a) a firsttransition metal oxide which is the primary constituent of the ECregion, b) a mixed transition metal oxide which is the primaryconstituent of the CE region, and c) a mixture including an alkali metalcompound, the first transition metal and the mixed transition metaloxide, the mixture being the primary constituent of the IC region. Inone embodiment, the mixed transition metal oxide includes the firsttransition metal and a second transition metal selected from the groupconsisting of nickel, tantalum, titanium, vanadium, chromium, cerium,cobalt, copper, iridium, iron, manganese, molybdenum, niobium,palladium, praseodymium, rhodium and ruthenium. In one embodiment, themixed transition metal oxide does not include the first transitionmetal. In one embodiment, the alkali metal is lithium cation, eitherassociated with a compound or associated with the material matrix as atransportable ion during operation of the EC element.

One embodiment is a method of fabricating an electrochromic deviceincluding: (a) forming either an electrochromic layer including anelectrochromic material or a counter electrode layer including a counterelectrode material; (b) forming an intermediate layer over theelectrochromic layer or the counter electrode layer, where theintermediate layer includes an oxygen rich form of at least one of theelectrochromic material, the counter electrode material and anadditional material, where the additional material includes distinctelectrochromic or counter electrode material, the intermediate layer notsubstantially electronically-insulating; (c) exposing the intermediatelayer to lithium; and (d) heating the stack formed in order to convertat least part of the intermediate layer to a region, coextensive withthe area of the intermediate layer, including anelectronically-insulating ionically-conducting material and the materialof the intermediate layer.

Because the intermediate layer may be formed from an oxygen rich form ofthe EC and/or CE material, the EC layer and/or CE layer can beunderstood to be formed to include a heterogeneous composition (e.g.,including both the oxygen rich portion and the non-oxygen rich portion).

Method Of Fabricating Electrochromic Windows

Deposition of the Electrochromic Stack

As mentioned above, one aspect of the embodiments is a method offabricating an electrochromic window. In a broad sense, the methodincludes sequentially depositing on a substrate (i) a cathodicallycoloring electrochromic layer, (ii) an optional ion conducting layer,and (iii) an anodically coloring counter electrode layer to form a stackin which either (a) the ion conducting layer separates the cathodicallycoloring electrochromic layer and the anodically coloring counterelectrode layer, or (b) the cathodically coloring electrochromic layeris in physical contact with the anodically coloring counter electrodelayer. In various embodiments, the counter electrode layer is depositedto be heterogeneous with respect to composition and/or morphology. Forinstance, the counter electrode may be deposited to include sublayers insome cases. In some embodiments, the counter electrode layer isdeposited to include a graded composition. The gradient may be in adirection perpendicular to the surface of the layer.

The sequential deposition may employ a single integrated depositionsystem having a controlled ambient environment in which the pressure,temperature, and/or gas composition are controlled independently of anexternal environment outside of the integrated deposition system, andthe substrate may not leave the integrated deposition system at any timeduring the sequential deposition of the electrochromic layer, theoptional ion conducting layer, and the counter electrode layer.(Examples of integrated deposition systems which maintain controlledambient environments are described in more detail below in relation toFIGS. 9A-9E.) The gas composition may be characterized by the partialpressures of the various components in the controlled ambientenvironment. The controlled ambient environment also may becharacterized in terms of the number of particles or particle densities.In certain embodiments, the controlled ambient environment containsfewer than 350 particles (of size 0.1 micrometers or larger) per m³. Incertain embodiments, the controlled ambient environment meets therequirements of a class 1000 clean room (US FED STD 209E), or a class100 clean room (US FED STD 209E). In certain embodiments, the controlledambient environment meets the requirements of a class 10 clean room (USFED STD 209E). The substrate may enter and/or leave the controlledambient environment in a clean room meeting class 1000, class 100 oreven class 10 requirements.

Typically, but not necessarily, this method of fabrication is integratedinto a multistep process for making an electrochromic window usingarchitectural glass as the substrate, but methods are not so limited.Electrochromic mirrors and other devices may be fabricated using some orall of the operations and approaches described herein. Further detailsrelated to processes for fabricating electrochromic windows arediscussed in U.S. patent application Ser. No. 12/645,111, incorporatedby reference above.

The method for depositing the electrochromic stack may includesequentially depositing on a substrate (i) a cathodically coloring EClayer, (ii) an optional IC layer, and (iii) an anodically coloring CElayer to form a stack in which either (a) the IC layer separates the EClayer and the CE layer, or (b) the EC layer and CE layer are in physicalcontact with one another. The method may be performed in a singleintegrated deposition system having a controlled ambient environment inwhich the pressure and/or gas composition are controlled independentlyof an external environment outside of the integrated deposition system,and the substrate in various cases may not leave the integrateddeposition system at any time during the sequential deposition of the EClayer, the optional IC layer, and the CE layer. In one embodiment, eachof the sequentially deposited layers is physical vapor deposited. Ingeneral the layers of the electrochromic device may be deposited byvarious techniques including physical vapor deposition, chemical vapordeposition, plasma enhanced chemical vapor deposition, and atomic layerdeposition, to name a few. The term physical vapor deposition as usedherein includes the full range of art understood PVD techniquesincluding sputtering, evaporation, ablation, and the like.

FIG. 5 depicts one embodiment of process 720 for forming anelectrochromic stack. First the cathodically coloring EC layer isdeposited on the substrate, process 722, then the optional IC layer maybe deposited, process 724 (as noted above, in certain embodiments the IClayer, and therefore process 724, are omitted), then the heterogeneousanodically coloring CE layer may be deposited, process 726. Theheterogeneous CE layer may be deposited in two or more steps in somecases. For instance, where the CE layer includes sublayers, each of thesublayers may be deposited in a distinct process/step. The reverse orderof deposition is also an embodiment, that is, where the CE layer isdeposited first, then the optional IC layer and then the EC layer. Inone embodiment, each of the electrochromic layer, the optional ionconducting layer, and the counter electrode layer is a solid phaselayer. In these or other embodiments, each of the electrochromic layer,the optional ion conducting layer, and the counter electrode layer mayinclude only inorganic material.

It should be understood that while certain embodiments are described interms of a counter electrode layer, an ion conductor layer, and anelectrochromic layer, any one or more of these layers may be composed ofone or more sublayers, which may have distinct compositions, sizes,morphologies, charge densities, optical properties, etc. Further any oneor more of the device layers may have a graded composition or a gradedmorphology in which the composition or morphology, respectively, changesover at least a portion of the thickness of the layer.

Many of the embodiments herein are presented in the context of a counterelectrode layer that includes a heterogeneous composition and/ormorphology. The described heterogeneous counter electrode layer may beused in conjunction with other layers or regions (e.g., electrochromiclayers, interfacial regions where an EC layer contacts a CE layer, etc.)that include gradations and/or sublayers with differing compositionsand/or morphologies.

In one example, the concentration of oxygen, a dopant, or charge carriervaries within a given layer, at least as the layer is fabricated. Inanother example, the morphology of a layer varies from crystalline toamorphous. Such graded composition or morphology may be chosen to impactthe functional properties of the device. In some cases, additionallayers may be added to the stack. In one example a heat spreader layeris interposed between one or both TCO layers and the EC stack. A heatspreader layer is made of material(s) that have high thermalconductivity and thus can spread heat efficiently across the stack.

Also, as described above, the electrochromic devices of certainembodiments utilize ion movement between the electrochromic layer andthe counter electrode layer via an ion conducting layer. In someembodiments these ions (or neutral precursors thereof) are introduced tothe stack as one or more layers that eventually intercalate into thestack. Such layers may be deposited before, during, and/or afterdeposition of the other layers (e.g., EC layer, IC layer, CE layer) inthe stack. Alternatively (or in addition), one or more lithiation stepsmay be performed as an intermediate step occurring between stepsperformed to deposit an electrode. For example, a counter electrodelayer may be deposited by depositing a first sublayer, followed bydepositing lithium thereon, and then concluded by depositing one or moreadditional sublayers. In one embodiment, a first sublayer, optionally aflash layer, is deposited, followed by a second sublayer, followed bylithiation, then a third sublayer deposited on the second sublayer. Inanother embodiment, a first sublayer, optionally a flash layer, isdeposited, followed by a second sublayer, then a third sublayerdeposited on the second sublayer, lithium is then deposited on the thirdsublayer. In some embodiments, a DMIL or capping layer is deposited onthe third sublayer.

The sublayers deposited before vs. after lithiation may have the same ordifferent compositions and/or morphologies. Lithiation may also beperformed during deposition of a single sublayer, e.g., the material ofthe sublayer includes excess lithium such that deposition of thatsublayer provides, e.g., sufficient lithium for the remainder of theelectrochromic device stack. This result may be achieved, e.g., byco-sputtering lithium with the sublayer material or where the sublayermaterial already includes lithium. Such approaches may have certainadvantages such as better separating the lithium from the indium tinoxide (ITO) or other material of a conductive layer, which improvesadhesion and prevents undesirable side reactions.

In some embodiments the ions are introduced into the stack concurrentlywith one or more of the electrochromic layer, the ion conducting layer,and the counter electrode layer. In one embodiment, where lithium ionsare used, lithium is, e.g., sputtered along with the material used tomake the one or more of the stack layers or sputtered as part of amaterial that includes lithium (e.g., by a method employing lithiumnickel tungsten tantalum oxide or another lithium containing material).In one embodiment, the IC layer is deposited via sputtering a lithiumsilicon aluminum oxide target. In another embodiment, the Li isco-sputtered along with silicon aluminum in order to achieve the desiredfilm.

Referring again to process 722 in FIG. 5, in one embodiment, depositingthe electrochromic layer comprises depositing WO_(x), e.g., where x isless than 3.0 and at least about 2.7. In this embodiment, the WO_(x) hasa substantially nanocrystalline morphology. In some embodiments, theelectrochromic layer is deposited to a thickness of between about 200 nmand 700 nm. In one embodiment, depositing the electrochromic layerincludes sputtering tungsten from a tungsten containing target.Particular deposition conditions for forming a WO_(x) electrochromiclayer are further discussed in U.S. patent application Ser. No.12/645,111, which is incorporated by reference above.

It should be understood that while deposition of the EC layer isdescribed in terms of sputtering from a target, other depositiontechniques are employed in some embodiments. For example, chemical vapordeposition, atomic layer deposition, and the like may be employed. Eachof these techniques, along with PVD, has its own form of material sourceas is known to those of skill in the art.

Referring again to FIG. 5, operation 724, once the EC layer isdeposited, the optional IC layer may be deposited. Electrochromicdevices that operate by lithium ion intercalation are well suited forthe demanding conditions of architectural windows. Suitable lithium ionconductor layer materials include lithium silicate, lithium aluminumsilicate, lithium oxide, lithium tungstate, lithium aluminum borate,lithium borate, lithium zirconium silicate, lithium niobate, lithiumborosilicate, lithium phosphosilicate, lithium nitride, lithiumoxynitride, lithium aluminum fluoride, lithium phosphorus oxynitride(LiPON), lithium lanthanum titanate (LLT), lithium tantalum oxide,lithium zirconium oxide, lithium silicon carbon oxynitride (LiSiCON),lithium titanium phosphate, lithium germanium vanadium oxide, lithiumzinc germanium oxide, and other ceramic materials that allow lithiumions to pass through them while having a high electrical resistance(blocking electron movement therethrough). Particular depositionconditions for forming an IC layer in situ are further discussed in U.S.patent application Ser. No. 12/645,111, and in U.S. Pat. No. 9,261,751,each of which is incorporated by reference above. In certainembodiments, depositing the ion conducting layer includes depositing theion conducting layer to a thickness of between about 10 and 100 nm.

Referring again to FIG. 5, operation 726, after the optional IC layer isdeposited, the anodically coloring CE layer is deposited. In someembodiments where the IC layer is omitted, operation 726 may followoperation 722. The anodically coloring CE layer may be deposited toinclude a heterogeneous composition and/or morphology as describedabove. In various cases, operation 726 involves depositing two or moresublayers of anodically coloring counter electrode material. One ofthese sublayers may be a flash layer as described above. In these orother cases, the counter electrode may be deposited to include a gradedcomposition.

In one embodiment, depositing the counter electrode layer includesdepositing a layer or sublayer(s) of nickel-tungsten-tantalum-oxide(NiWTaO). In a specific embodiment, depositing the counter electrodelayer includes sputtering a target including about 30% (by weight) toabout 70% of tungsten in nickel and/or tantalum in an oxygen containingenvironment to produce a layer of nickel tungsten tantalum oxide (thetantalum being provided by a tungsten/nickel/tantalum target at anappropriate composition, or by another target, or through another sourcesuch as an evaporated tantalum source). In another embodiment the targetis between about 40% and about 60% tungsten in nickel (and/or tantalum),in another embodiment between about 45% and about 55% tungsten in nickel(and/or tantalum), and in yet another embodiment about 51% tungsten innickel (and/or tantalum).

In certain embodiments where the anodically coloring counter electrodelayer includes a layer or sublayer(s) of NiWTaO, many deposition targetsor combinations of targets may be used to deposit the NiWTaO materials.For instance, individual metal targets of nickel, tungsten, and tantalumcan be used. In other cases at least one of the targets includes analloy. For instance, an alloy target of nickel-tungsten can be usedtogether with a metal tantalum target. In another case, an alloy targetof nickel-tantalum can be used together with a metal tungsten target. Ina further case, an alloy of tungsten-tantalum can be used together witha metal nickel target. In yet a further case, an alloy target containinga nickel-tungsten-tantalum material may be used. Moreover, any of thelisted targets can be provided as an oxide. Oftentimes, sputteringoccurs in the presence of oxygen, and such oxygen is incorporated intothe material. Sputter targets containing oxygen may be usedalternatively or in addition to an oxygen-containing sputteringatmosphere.

The sputtering target(s) for forming the anodically coloring counterelectrode material may have compositions that permit the counterelectrode layer or sublayers to be formed at any of the compositionsdescribed herein. Further, the sputtering target(s) for forming theanodically coloring counter electrode material may be positioned in away that permits the material to be formed as desired, for example toform heterogeneous counter electrode layers (e.g., having heterogeneouscompositions, heterogeneous morphologies, sublayers, gradedcompositions, etc.) as described herein. In one example where a singlesputter target is used to form a NiWTaO material, the sputter target mayhave a composition that matches the composition of any of the NiWTaOmaterials disclosed herein. In other examples a combination of sputtertargets are used, and the composition of the combined targets allows fordeposition at any of the NiWTaO compositions (or other counter electrodematerials) disclosed herein.

In one embodiment, the gas composition used when forming the CE (or asublayer therein) contains between about 30% and about 100% oxygen, inanother embodiment between about 75% and about 100% oxygen, in yetanother embodiment between about 95% and about 100% oxygen, in anotherembodiment about 100% oxygen. In one embodiment, the power density usedto sputter a CE target is between about 2 Watts/cm² and about 50Watts/cm² (determined based on the power applied divided by the surfacearea of the target); in another embodiment between about 5 Watts/cm² andabout 20 Watts/cm²; and in yet another embodiment between about 8Watts/cm² and about 10 Watts/cm', in another embodiment about 8Watts/cm². In some embodiments, the power delivered to effect sputteringis provided via direct current (DC). In other embodiments, pulsed DC/ACreactive sputtering is used. In one embodiment, where pulsed DC/ACreactive sputtering is used, the frequency is between about 20 kHz andabout 400 kHz, in another embodiment between about 20 kHz and about 50kHz, in yet another embodiment between about 40 kHz and about 50 kHz, inanother embodiment about 40 kHz.

The pressure in the deposition station or chamber, in one embodiment, isbetween about 1 and about 50 mTorr, in another embodiment between about20 and about 40 mTorr, in another embodiment between about 25 and about35 mTorr, in another embodiment about 30 mTorr. In some cases, a nickeltungsten oxide NiWO ceramic target is sputtered with, e.g., argon andoxygen. In one embodiment, the NiWO is between about 15% (atomic) Ni andabout 60% Ni; between about 10% W and about 40% W; and between about 30%O and about 75% O. In another embodiment, the NiWO is between about 30%(atomic) Ni and about 45% Ni; between about 10% W and about 25% W; andbetween about 35% O and about 50% O. In one embodiment, the NiWO isabout 42% (atomic) Ni, about 14% W, and about 44% O. In anotherembodiment, depositing the counter electrode layer includes depositingthe counter electrode layer to a thickness of between about 150 and 350nm; in yet another embodiment between about 200 and about 250 nm thick.The above conditions may be used in any combination with one another toeffect deposition of a heterogeneous counter electrode layer.

The sputtering process for forming each portion of the CE layer mayutilize one or more sputter targets. Different sputter targets may beused to form a variety of CE materials. Generally, the sputter targetsfor forming the CE layer include the elements that are to be present inthe deposited CE layer (with oxygen optionally being provided in thetarget(s) themselves and/or by a sputter gas). In some cases, theelements of the CE layer are all provided together in a single target.In other cases, all the elements of the CE layer except oxygen areprovided together in a single target. In other cases, different sputtertargets may include different materials, and the targets can be usedtogether to form a desired CE material. Much of the discussion hereinregarding sputter targets is in the context of forming a NiWTa0material. However, the teachings herein are applicable to forming any ofthe disclosed materials, so long as the targets provided include theappropriate elements at an appropriate composition.

In one example where one sputter target is used to form a layer ofNiWTa0, the target may include nickel, tungsten, and tantalum. In somecases the sputter target also includes oxygen. In some cases, multipletargets may be provided, with the composition of the targets being thesame or different from one another. In one example in the context offorming a NiWTaO layer, at least one of the nickel, tungsten, andtantalum materials may be provided in a separate target. Similarly,where one sputter target is used to form a layer of NiWO, the target mayinclude nickel and tungsten, optionally with oxygen. The nickel andtungsten can also be provided in separate targets. Other CE materialsmay similarly be deposited using one or more targets that may have thesame or differing compositions compared to one another.

The sputter target may include a grid or other overlapping shape wheredifferent portions of the grid include the different relevant materials(e.g., in the context of forming a NiWTaO layer or sublayer, certainportions of the grid may include elemental nickel, elemental tungsten,elemental tantalum, a nickel-tungsten alloy, a nickel-tantalum alloy,and/or a tungsten-tantalum alloy). In some cases, a sputter target maybe an alloy of the relevant materials (e.g., in the context of forming aNiWTaO layer or sublayer, two or more of nickel, tungsten, and tantalummay be provided as an alloy). Where two or more sputter targets areused, each sputter target may include at least one of the relevantmaterials (e.g., in the context of forming a NiWTaO layer or sublayer,at least one elemental and/or alloy form of nickel, tungsten, and/ortantalum, any of which can be provided in oxide form, may be present ineach target). The sputter targets may overlap in some cases. The sputtertargets may also rotate in some embodiments. As noted, the counterelectrode layer is typically an oxide material. Oxygen may be providedas a part of the sputter target and/or sputter gas. In certain cases,the sputter targets are substantially pure metals, and sputtering isdone in the presence of oxygen to form the oxide.

In one embodiment, in order to normalize the rate of deposition of theCE layer, multiple targets are used so as to obviate the need forinappropriately high power (or other inappropriate adjustment to desiredprocess conditions) to increase deposition rate. In one embodiment, thedistance between the CE target (cathode or source) to the substratesurface is between about 35 mm and about 150 mm; in another embodimentbetween about 45 mm and about 130 mm; and in another embodiment betweenabout 70 mm and about 100 mm.

As noted, one or more rotating targets may be used in some cases. Invarious cases, a rotating target may include an interior magnet. FIG. 6Apresents a view of a rotating target 900. Inside the rotating target 900is a magnet 902, which (when the target is supplied with appropriatepower) causes material to sputter off of the target surface 904 in asputter cone 906 (sputter cones are also sometimes referred to assputter plasmas). The magnet 902 may extend along the length of thesputter target 900. In various embodiments, the magnet 902 may beoriented to extend radially outward such that the resulting sputter cone906 emanates from the sputter target 900 in a direction normal to thetarget's surface 904 (the direction being measured along a central axisof the sputter cone 906, which typically corresponds to the averagedirection of the sputter cone 906). The sputter cone 906 may be v-shapedwhen viewed from above, and may extend along the height of the target900 (or the height of the magnet 902 if not the same as the height ofthe target 900). The magnet 902 inside the rotating target 900 may befixed (i.e., though the surface 904 of the target 900 rotates, themagnet 902 within the target 900 does not rotate) such that the sputtercone 906 is also fixed. The small circles/dots depicted in the sputtercone 906 represent sputtered material that emanates from the sputtertarget 900. Rotating targets may be combined with other rotating targetsand/or planar targets as desired.

In one example, two rotating targets are used to deposit a NiWTaOanodically coloring CE layer (or a sublayer within the anodicallycoloring CE layer): a first target including nickel and tungsten, and asecond target including tantalum (either or both optionally in oxideform). FIG. 6B presents a top down view of a deposition system fordepositing an anodically coloring layer or sublayer in this manner. Thenickel tungsten target 910 and the tantalum target 912 each include aninterior magnet 914. The magnets 914 are angled toward one another suchthat the sputter cones 916 and 918 from the nickel tungsten target 910and tantalum target 912, respectively, overlap. FIG. 6B also shows asubstrate 920 passing in front of the targets 910 and 912. As shown, thesputter cones 916 and 918 closely overlap where they impact thesubstrate 920. In some embodiments, the sputter cones from varioussputter targets may closely overlap with one another (e.g., thenon-overlapping area over which only a single sputter cone reaches whendepositing on a substrate is less than about 10%, for example less thanabout 5% of the total area over which either sputter cone reaches). Inother embodiments, the sputter cones may diverge from one another to agreater degree such that either or both of the sputter cones has anon-overlapping area that is at least about 10%, for example at leastabout 20%, or at least about 30%, or at least about 50%, of the totalarea over which either sputter cone reaches.

In a similar embodiment to the one shown in FIG. 6B, also presented inthe context of forming a NiWTaO CE layer (or sublayer), one sputtertarget is tungsten and the other is an alloy of nickel and tantalum(either or both targets optionally being in oxide form). Similarly, onesputter target may be nickel and the other may be an alloy of tungstenand tantalum (either or both target optionally being in oxide form). Ina related embodiment, three sputter targets are used: a tantalum target,a nickel target, and a tungsten target (any of which can optionally bein oxide form). The sputter cones from each of the three targets mayoverlap by angling the magnets as appropriate. Also, shielding, gratingsand/or other additional plasma shaping elements may be used to aid increating the appropriate plasma mixture to form the NiWTaO. Similarly,in the context of other anodically coloring counter electrode materials,any combination of targets including elemental metals, alloys, and/oroxides can be used, assuming that the targets include the materials(other than oxygen) to be incorporated into the relevant layer orsublayer being formed.

Various sputter target designs, orientations, and implementations arefurther discussed in U.S. Pat. No. 9,261,751, which is incorporated byreference above.

The density and orientation/shape of material that sputters off of asputter target depends on various factors including, for example, themagnetic field shape and strength, pressure, and power density used togenerate the sputter plasma. The distance between adjacent targets, aswell as the distance between each target and substrate, can also affecthow the sputter plasmas will mix and how the resulting material isdeposited on the substrate.

In certain embodiments, two different types of sputter targets areprovided to deposit a single layer or sublayer in an electrochromicstack: (a) primary sputter targets, which sputter material onto asubstrate, and (b) secondary sputter targets, which sputter materialonto the primary sputter targets. The primary and secondary sputtertargets may include any combination of metal, metal alloys, and metaloxides that achieve a desired composition in a deposited layer. In oneparticular example in the context of a NiWTaO counter electrodematerial, a primary sputter target includes an alloy of nickel andtungsten, and a secondary sputter target includes tantalum. In anotherexample a primary sputter target includes tantalum and a secondarysputter target includes an alloy of nickel and tungsten. These sputtertargets may be used together to deposit an anodically coloring layer (orsublayer) of NiWTaO. Other combinations of alloys (e.g.,nickel-tantalum, tungsten-tantalum, and alloys of other metals) andmetals (e.g., nickel, tungsten, and other metals) can also be used asappropriate to form NiWTaO or other desired materials. Any sputtertarget may be provided as an oxide.

A number of different setups are possible when using both primary andsecondary sputter targets. FIGS. 7A and 7B present top-down views of oneembodiment of a deposition station for depositing a multi-componentanodically coloring counter electrode material. Though presented in thespecific context of depositing a counter electrode material, the sputtertarget configurations discussed herein may be used to deposit anymaterial in the electrochromic stack, provided that the targets are ofappropriate compositions to deposit the desired material in the stack. Aprimary sputter target 1001 and a secondary sputter target 1002 areprovided, each with an internal magnet 1003. Each sputter target in thisexample is a rotating sputter target, though planar or other shapedtargets may be used as well. The targets may rotate in the samedirection or in opposite directions. The secondary sputter target 1002sputters material onto the primary sputter target 1001 when no substrate1004 is present between the two targets, as shown in FIG. 7A. Thisdeposits material from the secondary sputter target 1002 onto theprimary sputter target 1001. Then, as the substrate 1004 moves intoposition between the two targets, sputtering from the secondary sputtertarget 1002 ceases and sputtering from the primary sputter target 1001onto the substrate 1004 begins, as shown in FIG. 7B.

When material is sputtered off of the primary sputter target 1001 anddeposited onto the substrate 1004, the deposited material includesmaterial that originated from both the primary and secondary sputtertargets 1001 and 1002, respectively. In effect, this method involvesin-situ formation of an intermixed sputter target surface on the primarysputter target 1001. One advantage of this method is that a freshcoating of material from the secondary sputter target 1002 isperiodically deposited on the surface of the primary sputter target1001. The intermixed materials are then delivered together to thesubstrate 1004. In a particular example in the context of forming aNiWTaO counter electrode material, each of the primary and secondarysputter targets may include any combination of tantalum, tungsten,nickel, and/or alloys thereof, optionally in oxide form.

In a related embodiment shown in FIG. 7C, a secondary sputter target1022 is positioned behind a primary sputter target 1021, and a substrate1024 passes in front of the primary sputter target 1021 such that itdoes not block the line of sight between the two targets 1021 and 1022.Each of the sputter targets may include a magnet 1023. In thisembodiment, there is no need to periodically stop sputtering from thesecondary sputter target 1021 onto the primary sputter target 1022.Instead, such sputtering can occur continuously. Where the primarysputter target 1021 is located in between the substrate 1024 and thesecondary sputter target 1022 (e.g., there is no line of sight betweenthe secondary sputter target 1022 and the substrate 1024), the primarysputter target 1021 should rotate such that material that is depositedonto the primary sputter target 1021 can be sputtered onto the substrate1024. There is more flexibility in the design of the secondary sputtertarget 1022. In a related embodiment, the secondary sputter target maybe a planar or other non-rotating target. Where two rotating targets areused, the targets may rotate in the same direction or in oppositedirections.

In similar embodiments, the secondary sputter target (e.g., thesecondary target in FIGS. 7A-7C) may be replaced with another secondarymaterial source. The secondary material source may provide material tothe primary sputter target through means other than sputtering. In oneexample, the secondary material source provides evaporated material tothe primary sputter target. The evaporated material may be any componentof a layer being deposited. In various examples the evaporated materialis an elemental metal or metal oxide. Particular examples of evaporatedmaterial include tantalum, tungsten, and nickel, which may be used toform a NiWTaO anodically coloring counter electrode material. In oneembodiment, elemental tantalum is evaporated onto a primary sputtertarget including a mixture and/or alloy of nickel and tungsten. Othermaterials may also be provided in this manner to form layers orsublayers of other compositions. Where a secondary material sourceprovides evaporated material, the secondary material source may beprovided at any location relative to the primary sputter target andsubstrate. In some embodiments the secondary material source is providedsuch that it is behind and deposits primarily on the primary sputtertarget, much like the setup shown in FIG. 7C.

Where both a primary and a secondary sputter target are used, thesecondary sputter target may be operated at a potential that is cathodiccompared to the potential of the primary sputter target (which isalready cathodic). Alternatively, the targets may be operatedindependently. Still further, regardless of relative target potentials,neutral species ejected from the secondary target will deposit on theprimary target. Neutral atoms will be part of the flux, and they willdeposit on a cathodic primary target regardless of relative potentials.

In various embodiments, reactive sputtering may be used to deposit oneor more materials in the electrochromic stack. FIG. 8 is a diagramshowing the sputtering deposition rate from a sputter target as afunction of oxygen concentration at a fixed power. As shown in FIG. 8,there is a strong hysteresis effect related to the oxygen concentrationprofile the target has been exposed to/operated under. For instance,when starting from a low oxygen concentration and increasing to a higheroxygen concentration, the deposition rate stays fairly high until theoxygen concentration reaches a point at which the sputter target formsan oxide that cannot be removed from the target sufficiently quickly. Atthis point the deposition rate drops down, and the sputter targetessentially forms a metal oxide target. The deposition rate for an oxidetarget is generally much lower than the deposition rate for a metaltarget, all other conditions being equal. The relatively high depositionrate region in FIG. 8 corresponds to a metal deposition regime, whilethe relatively low deposition rate region corresponds to a metal oxidedeposition regime. When the target is initially exposed to/operatedunder a high oxygen concentration then exposed to/operated under arelatively lower concentration, the deposition rate stays fairly lowuntil the oxygen concentration reaches a point at which the depositionrate jumps up to a higher level. As shown in FIG. 8, the oxygenconcentration at which these changes take place is different dependingon whether the oxygen concentration is increasing or decreasing. Theexact oxygen concentrations at which the regime changes occur can becontrolled by changing the target power density and magnetic strength ofthe internal magnet 1003. For example, if one target is sputtering asubstantially higher flux of metal atoms from the surface (due to higherpower and/or magnetic strength), that target would likely stay in themetal deposition regime, compared to a target which is sputtering a verylow flux of metal atoms. Such hysteresis effects can be used toadvantage in a deposition process.

In certain embodiments where two or more sputter targets are used todeposit a material in the electrochromic stack, one target may beoperated in the metal deposition regime and another target may beoperated in the metal oxide deposition regime. By controlling the targetpower density, magnetic strength of the internal magnet 1003, and theatmosphere to which each target is exposed/operated under over time, itis possible to operate at both of these regimes simultaneously. In oneexample, a first nickel tungsten target is exposed to a relatively lowconcentration of oxygen and then brought to a mid-level concentration ofoxygen such that it operates in the metal deposition regime. A secondtantalum target is exposed to a relatively high concentration of oxygenand then brought to a mid-level concentration of oxygen such that itoperates in the metal oxide deposition regime. The two targets can thenbe brought together, still exposed to the mid-level oxygenconcentration, where they are used to deposit material onto a substrateunder both regimes (the first target continuing to operate under themetal deposition regime and the second target continuing to operateunder the metal oxide deposition regime).

The different atmosphere exposures for each target may not be needed inmany cases. Other factors besides different historical oxygen exposurecan result in the targets operating under the different depositionregimes. For instance, the targets may have different hysteresis curvesdue to the different material in the targets. As such, the targets maybe able to operate under different regimes even if they are historicallyexposed to and operated under the same atmospheric oxygen conditions.Further, the amount of power applied to each target can significantlyaffect the deposition regime experienced by each target. In one example,therefore, one target is operated under a metal deposition regime andanother target is operated under a metal oxide deposition regime due tothe different powers applied to each target. This approach may be easierbecause it does not require separating the targets from one another suchthat they can be exposed to different oxygen concentrations. Oneadvantage to operating the targets at different points in the hysteresiscurves is that the composition of a deposited material can be closelycontrolled.

It should be understood that while the order of deposition operations isdepicted in FIG. 5 to be first EC layer, second IC layer, and finally CElayer, the order can be reversed in various embodiments. In other words,when as described herein “sequential” deposition of the stack layers isrecited, it is intended to cover the following “reverse” sequence, firstCE layer, second IC layer, and third EC layer, as well the “forward”sequence described above. Both the forward and reverse sequences canfunction as reliable high-quality electrochromic devices. Further, itshould be understood that conditions recited for depositing the variousEC, IC, and CE materials recited here, are not limited to depositingsuch materials. Other materials may, in some cases, be deposited underthe same or similar conditions. Moreover, the IC layer may be omitted incertain cases. Further, non-sputtering deposition conditions may beemployed in some embodiments to create the same or similar depositedmaterials as those described herein.

Since the amount of charge each of the EC and the CE layers can safelyhold varies, depending on the material used, the relative thickness ofeach of the layers may be controlled to match capacity as appropriate.In one embodiment, the electrochromic layer includes tungsten oxide andthe counter electrode includes nickel tungsten tantalum oxide (providedin a counter electrode layer or sublayer), and the ratio of thicknessesof the electrochromic layer to the counter electrode layer is betweenabout 1.7:1 and 2.3:1, or between about 1.9:1 and 2.1:1 (with about 2:1being a specific example).

As mentioned, the EC stack is fabricated in an integrated depositionsystem where the substrate does not leave the integrated depositionsystem at any time during fabrication of the stack. In one embodiment,the second TCO layer is also formed using the integrated depositionsystem where the substrate does not leave the integrated depositionsystem during deposition of the EC stack and the TCO layer. In oneembodiment, all of the layers are deposited in the integrated depositionsystem where the substrate does not leave the integrated depositionsystem during deposition; that is, in one embodiment the substrate is aglass sheet and a stack including the EC layer, the optional IC layerand the CE layer, sandwiched between a first and a second TCO layer, isfabricated on the glass where the glass does not leave the integrateddeposition system during deposition. In another implementation of thisembodiment, the substrate is glass with a diffusion barrier depositedprior to entry in the integrated deposition system. In anotherimplementation the substrate is glass and the diffusion barrier, a stackincluding the EC layer, the optional IC layer and the CE layer,sandwiched between a first and a second TCO layer, are all deposited onthe glass where the glass does not leave the integrated depositionsystem during deposition.

As mentioned above, lithium may be provided with the EC, CE and/or IClayers as they are formed on the substrate. This may involve, forexample, co-sputtering of lithium together with the other materials of agiven layer (e.g., tungsten and oxygen, in some cases with additional ordifferent elements as appropriate). In certain embodiments the lithiumis delivered via a separate process and allowed to diffuse or otherwiseincorporate into the EC, CE and/or IC layers. In some embodiments, onlya single layer in the electrochromic stack is lithiated. For example,only the anodically coloring CE layer (or a sublayer therein) islithiated in some examples. In other cases, only the cathodicallycoloring EC layer is lithiated. In still other cases, only the IC layeris lithiated. In other embodiments, two or more of the EC, IC, and CElayers (including sublayers) are lithiated. Particular conditions forlithiation are further discussed in U.S. patent application Ser. No.12/645,111, which is incorporated by reference above.

In some embodiments, the electrochromic stack includes a counterelectrode layer or sublayer in direct physical contact with anelectrochromic layer, without an ion conducting layer in between. Insome such cases, the electrochromic and/or counter electrode layer mayinclude an oxygen-rich portion (e.g., an oxygen rich sublayer or anoxygen rich portion of a graded layer in various cases) in contact withthe other of these layers. The oxygen-rich portion may include theelectrochromic material or counter electrode material, with a higherconcentration of oxygen than in the remaining portion of theelectrochromic layer and/or counter electrode layer. Electrochromicdevices fabricated according to such a design are further discussed anddescribed in U.S. Pat. No. 8,300,298, filed Apr. 30, 2010, which isincorporated by reference above.

In one aspect of the disclosed embodiments, a method of fabricating anelectrochromic device is provided, the method including: depositing anelectrochromic layer comprising a cathodically coloring electrochromicmaterial; and depositing a counter electrode layer by: depositing afirst anodically tinting sublayer comprising Ni_(a)W_(b)A_(c)O_(d),where a, b, and d are greater than zero, depositing a second anodicallytinting sublayer comprising Ni_(e)W_(f)B_(g)O_(h), where e, f, and h aregreater than zero, where at least one of c and g are greater than zero,and where each of A and B, when present, is independently selected fromthe group consisting of: silver (Ag), aluminum (Al), arsenic (As), gold(Ag), boron (B), barium (Ba), beryllium (Be), bismuth (Bi), calcium(Ca), cadmium (Cd), cerium (Ce), cobalt (Co), chromium (Cr), copper(Cu), europium (Eu), iron (Fe), gallium (Ga), gadolinium (Gd), germanium(Ge), hafnium (Hf), mercury (Hg), indium (In), iridium (Ir), lanthanum(La), magnesium (Mg), manganese (Mn), molybdenum (Mo), niobium (Nb),neodymium (Nd), osmium (Os), protactinium (Pa), lead (Pb), palladium(Pd), praseodymium (Pr), promethium (Pm), polonium (Po), platinum (Pt),radium (Ra), rhenium (Re), rhodium (Rh), ruthenium (Ru), antimony (Sb),scandium (Sc), selenium (Se), silicon (Si), samarium (Sm), tin (Sn),strontium (Sr), tantalum (Ta), terbium (Tb), technetium (Tc), tellurium(Te), thorium (Th), titanium (Ti), thallium (Tl), uranium (U), vanadium(V), tungsten (W), yttrium (Y), zinc (Zn), and zirconium (Zr), andlithiating one or more anodically tinting sublayers of the counterelectrode layer, where the first anodically tinting sublayer ispositioned between the electrochromic layer and the second anodicallytinting sublayer, and where the first and second anodically tintingsublayers have different compositions. The electrochromic device may befabricated to include any of the materials/combinations ofmaterials/structures described herein.

As mentioned above, in certain embodiments, fabrication of theelectrochromic stack occurs in an integrated deposition system. Such anintegrated system may allow for deposition of the various layers in thestack without breaking vacuum. In other cases, one or more layers in thestack may be deposited by a process that requires removal from aprotected vacuum environment. For example, in some cases one or morelayers (e.g., a cathodically coloring EC layer) is deposited on asubstrate under vacuum using physical vapor deposition, then thesubstrate is removed from vacuum and an ion conductor layer is depositedusing a sol-gel (or other non-vacuum) process, and then the substrate isreturned to a vacuum environment for deposition of the anodicallycoloring counter electrode layer. Sol-gel processes involve producingsolid materials from small molecules. Monomers are converted into acolloidal solution that acts as the precursor for an integrated networkof discrete particles or network polymers. Examples of ion conductormaterials that may be deposited include, for example, silicate-basedstructures, lithium silicate, lithium aluminum silicate, lithiumaluminum borate, lithium borate, lithium zirconium silicate, lithiumniobate, lithium borosilicate, lithium phosphosilicate, lithium nitride,lithium aluminum fluoride, and other such lithium-based ceramicmaterials, silicas, or silicon oxides, silicon dioxide, and tantalumoxide.

Multistep Thermochemical Conditioning

Once the stack is deposited, the device may be subjected to a multistepthermo-chemical conditioning (MTC) process. This conditioning processmay promote formation of an ion conducting region within the device inembodiments where the device is deposited without a separate ionconducting layer, as such. MTC processes are further described in U.S.patent application Ser. No. 12/645,111, incorporated by reference above.

In certain embodiments, a different process flow may be used tofabricate an electrochromic device. Alternative process flows arefurther discussed in U.S. patent application Ser. No. 14/362,863, filedJun. 4, 2014, and titled “THIN-FILM DEVICES AND FABRICATION,” which isherein incorporated by reference in its entirety.

Integrated Deposition System

As explained above, an integrated deposition system may be employed tofabricate electrochromic devices on, for example, architectural glass.As described above, the electrochromic devices are used to make IGUswhich in turn are used to make electrochromic windows. The term“integrated deposition system” means an apparatus for fabricatingelectrochromic devices on optically transparent and translucentsubstrates. The apparatus has multiple stations, each devoted to aparticular unit operation such as depositing a particular component (orportion of a component) of an electrochromic device, as well ascleaning, etching, and temperature control of such device or portionthereof. The multiple stations are fully integrated such that asubstrate on which an electrochromic device is being fabricated can passfrom one station to the next without being exposed to an externalenvironment. Integrated deposition systems operate with a controlledambient environment inside the system where the process stations arelocated. A fully integrated system allows for better control ofinterfacial quality between the layers deposited. Interfacial qualityrefers to, among other factors, the quality of the adhesion betweenlayers and the lack of contaminants in the interfacial region. The term“controlled ambient environment” means a sealed environment separatefrom an external environment such as an open atmospheric environment ora clean room. In a controlled ambient environment at least one ofpressure and gas composition is controlled independently of theconditions in the external environment. Generally, though notnecessarily, a controlled ambient environment has a pressure belowatmospheric pressure; e.g., at least a partial vacuum. The conditions ina controlled ambient environment may remain constant during a processingoperation or may vary over time. For example, a layer of anelectrochromic device may be deposited under vacuum in a controlledambient environment and at the conclusion of the deposition operation,the environment may be backfilled with purge or reagent gas and thepressure increased to, e.g., atmospheric pressure for processing atanother station, and then a vacuum reestablished for the next operationand so forth.

In one embodiment, the system includes a plurality of depositionstations aligned in series and interconnected and operable to pass asubstrate from one station to the next without exposing the substrate toan external environment. The plurality of deposition stations comprise(i) a first deposition station containing one or more targets fordepositing a cathodically coloring electrochromic layer; (ii) a second(optional) deposition station containing one or more targets fordepositing an ion conducting layer; and (iii) a third deposition stationcontaining one or more targets for depositing a counter electrode layer.The second deposition station may be omitted in certain cases. Forinstance, the apparatus may not include any target for depositing aseparate ion conductor layer.

Further, any of the layers of the stack may be deposited in two or morestations. For example, where a counter electrode is deposited to includetwo or more sublayers, each of the sublayers may be deposited in adifferent station. Alternatively or in addition, two or more sublayerswithin a layer may be deposited within the same station, in some casesusing different targets in the same station. In one example, the counterelectrode is deposited in a single station and includes sublayers ofvarying composition (e.g., a NiWO sublayer and one or more NiWTaOsublayers, though other combinations of materials may also be used).Targets of different compositions may be provided at different portionsof the station to deposit the sublayers as desired. In another example,the counter electrode may be deposited in two stations, a first stationthat deposits a first sublayer (e.g., a thin flash layer) of a firstcounter electrode material (e.g., NiWO, or another anodically coloringcounter electrode material) and a second station that deposits one ormore additional sublayers of a second (or additional) counter electrodematerial(s) (e.g., one or more sublayers of NiWTaO or another anodicallycoloring counter electrode material). In another embodiment, a dedicatedstation is provided to deposit each layer or sublayer having a distinctcomposition. For instance, a first station may be provided to deposit afirst sublayer having a first composition (e.g., NiWO), a second stationmay be provided to deposit a second sublayer having a second composition(e.g., NiWTaO including about 7% tantalum), and a third station may beprovided to deposit a third sublayer having a third composition (e.g.,NiWTaO including about 14% tantalum).

The system also includes a controller containing program instructionsfor passing the substrate through the plurality of stations in a mannerthat sequentially deposits on the substrate (i) an electrochromic layer,(ii) an (optional) ion conducting layer, and (iii) a counter electrodelayer (as described herein) to form a stack. In one embodiment, theplurality of deposition stations are operable to pass a substrate fromone station to the next without breaking vacuum. In another embodiment,the plurality of deposition stations are configured to deposit theelectrochromic layer, the optional ion conducting layer, and the counterelectrode layer on an architectural glass substrate. In anotherembodiment, the integrated deposition system includes a substrate holderand transport mechanism operable to hold the architectural glasssubstrate in a vertical orientation while in the plurality of depositionstations. In yet another embodiment, the integrated deposition systemincludes one or more load locks for passing the substrate between anexternal environment and the integrated deposition system. In anotherembodiment, the plurality of deposition stations include at least twostations for depositing a layer selected from the group consisting ofthe cathodically coloring electrochromic layer, the ion conductinglayer, and the anodically coloring counter electrode layer.

In some embodiments, the integrated deposition system includes one ormore lithium deposition stations, each including a lithium containingtarget. In one embodiment, the integrated deposition system contains twoor more lithium deposition stations. In one embodiment, the integrateddeposition system has one or more isolation valves for isolatingindividual process stations from each other during operation. In oneembodiment, the one or more lithium deposition stations have isolationvalves. In this document, the term “isolation valves” means devices toisolate depositions or other processes being carried out one stationfrom processes at other stations in the integrated deposition system. Inone example, isolation valves are physical (solid) isolation valveswithin the integrated deposition system that engage while the lithium isdeposited. Actual physical solid valves may engage to totally orpartially isolate (or shield) the lithium deposition from otherprocesses or stations in the integrated deposition system. In anotherembodiment, the isolation valves may be gas knifes or shields, e.g., apartial pressure of argon or other inert gas is passed over areasbetween the lithium deposition station and other stations to block ionflow to the other stations. In another example, isolation valves may bean evacuated regions between the lithium deposition station and otherprocess stations, so that lithium ions or ions from other stationsentering the evacuated region are removed to, e.g., a waste streamrather than contaminating adjoining processes. This is achieved, e.g.,via a flow dynamic in the controlled ambient environment viadifferential pressures in a lithiation station of the integrateddeposition system such that the lithium deposition is sufficientlyisolated from other processes in the integrated deposition system.Again, isolation valves are not limited to lithium deposition stations.

FIG. 9A, depicts in schematic fashion an integrated deposition system800 in accordance with certain embodiments. In this example, system 800includes an entry load lock, 802, for introducing the substrate to thesystem, and an exit load lock, 804, for removal of the substrate fromthe system. The load locks allow substrates to be introduced and removedfrom the system without disturbing the controlled ambient environment ofthe system. Integrated deposition system 800 has a module, 806, with aplurality of deposition stations; an EC layer deposition station, an IClayer deposition station and a CE layer deposition station. In thebroadest sense, integrated deposition systems need not have load locks,e.g., module 806 could alone serve as the integrated deposition system.For example, the substrate may be loaded into module 806, the controlledambient environment established and then the substrate processed throughvarious stations within the system. Individual stations within anintegrated deposition systems can contain heaters, coolers, varioussputter targets and means to move them, RF and/or DC power sources andpower delivery mechanisms, etching tools e.g., plasma etch, gas sources,vacuum sources, glow discharge sources, process parameter monitors andsensors, robotics, power supplies, and the like.

FIG. 9B depicts a segment (or simplified version) of integrateddeposition system 800 in a perspective view and with more detailincluding a cutaway view of the interior. In this example, system 800 ismodular, where entry load lock 802 and exit load lock 804 are connectedto deposition module 806. There is an entry port, 810, for loading, forexample, architectural glass substrate 825 (load lock 804 has acorresponding exit port). Substrate 825 is supported by a pallet, 820,which travels along a track, 815. In this example, pallet 820 issupported by track 815 via hanging but pallet 820 could also besupported atop a track located near the bottom of apparatus 800 or atrack, e.g., mid-way between top and bottom of apparatus 800. Pallet 820can translate (as indicated by the double headed arrow) forward and/orbackward through system 800. For example during lithium deposition, thesubstrate may be moved forward and backward in front of a lithiumtarget, 830, making multiple passes in order to achieve a desiredlithiation. Pallet 820 and substrate 825 are in a substantially verticalorientation. A substantially vertical orientation is not limiting, butit may help to prevent defects because particulate matter that may begenerated, e.g., from agglomeration of atoms from sputtering, will tendto succumb to gravity and therefore not deposit on substrate 825. Also,because architectural glass substrates tend to be large, a verticalorientation of the substrate as it traverses the stations of theintegrated deposition system enables coating of thinner glass substratessince there are less concerns over sag that occurs with thicker hotglass.

Target 830, in this case a cylindrical target, is oriented substantiallyparallel to and in front of the substrate surface where deposition is totake place (for convenience, other sputter means are not depicted here).Substrate 825 can translate past target 830 during deposition and/ortarget 830 can move in front of substrate 825. The movement path oftarget 830 is not limited to translation along the path of substrate825. Target 830 may rotate along an axis through its length, translatealong the path of the substrate (forward and/or backward), translatealong a path perpendicular to the path of the substrate, move in acircular path in a plane parallel to substrate 825, etc. Target 830 neednot be cylindrical, it can be planar or any shape necessary fordeposition of the desired layer with the desired properties. Also, theremay be more than one target in each deposition station and/or targetsmay move from station to station depending on the desired process.

Integrated deposition system 800 also has various vacuum pumps, gasinlets, pressure sensors and the like that establish and maintain acontrolled ambient environment within the system. These components arenot shown, but rather would be appreciated by one of ordinary skill inthe art. System 800 is controlled, e.g., via a computer system or othercontroller, represented in FIG. 9B by an LCD and keyboard, 835. One ofordinary skill in the art would appreciate that embodiments herein mayemploy various processes involving data stored in or transferred throughone or more computer systems. Embodiments also relate to the apparatus,such computers and microcontrollers, for performing these operations.These apparatus and processes may be employed to deposit electrochromicmaterials of methods herein and apparatus designed to implement them.The control apparatus may be specially constructed for the requiredpurposes, or it may be a general-purpose computer selectively activatedor reconfigured by a computer program and/or data structure stored inthe computer. The processes presented herein are not inherently relatedto any particular computer or other apparatus. In particular, variousgeneral-purpose machines may be used with programs written in accordancewith the teachings herein, or it may be more convenient to construct amore specialized apparatus to perform and/or control the required methodand processes.

As mentioned, the various stations of an integrated deposition systemmay be modular, but once connected, form a continuous system where acontrolled ambient environment is established and maintained in order toprocess substrates at the various stations within the system. FIG. 9Cdepicts integrated deposition system 800 a, which is like system 800,but in this example each of the stations is modular, specifically, an EClayer station 806 a, an optional IC layer station 806 b and a CE layerstation 806 c. In a similar embodiment, the IC layer station 806 b isomitted. Modular form is not necessary, but it is convenient, becausedepending on the need, an integrated deposition system can be assembledaccording to custom needs and emerging process advancements. Forexample, lithium deposition stations (not shown) can be inserted atrelevant locations to provide lithium as desired for the various layersand sublayers.

FIG. 9D shows an embodiment of an integrated deposition system 800 d. Inthis embodiment, the integrated deposition system 800 d includes anentry load lock 802, two stations 850 and 851 for depositing sublayersof cathodically coloring electrochromic material, two stations 852 and853 for depositing sublayers of anodically coloring counter electrodematerial, and an exit load lock 804. The first sublayer of cathodicallycoloring electrochromic material is deposited in station 850. The secondsublayer of cathodically coloring electrochromic material is depositedin station 851, and may be an oxygen-rich form of the electrochromicmaterial deposited in station 850 in certain cases. In this embodiment,there is no separate station for depositing an ion conductor layer.After the second sublayer of electrochromic material is deposited, afirst sublayer of anodically coloring counter electrode material may bedeposited in station 852. The first sublayer may be a flash layer, forexample of NiWO or another anodically coloring material as describedherein. Next, a second sublayer of anodically coloring counter electrodematerial may be deposited in station 853. This layer may have anycomposition as described herein, and in one embodiment is NiWTaO. Invarious cases the second CE layer station 853 (or any other stationconfigured to deposit a CE material) is configured to deposit a sublayerhaving a graded composition.

FIG. 9E shows an additional embodiment of an integrated depositionsystem 800 e. This embodiment is similar to that shown in FIG. 9D, andfor the sake of brevity only the differences will be described. In thedeposition system of FIG. 9E, a lithiation station 854 is included afterthe second counter electrode station 853. In similar embodiments,additional lithiation stations may be provided. Further, the lithiationstations may be positioned between various pairs of stations shown inFIG. 9E, e.g., between stations 850 and 851, between stations 851 and852, between stations 852 and 853, between stations 853, and/or betweenstations 855 and 856.

Further, a capping layer station 855 is included after the lithiationstation 854. The capping layer station 855 may be used to deposit acapping layer. A capping layer is defined as a layer added to theelectrochromic device between the EC or CE layers and the TCO. In someembodiments, the capping layer is an anodically coloring material. Forexample, in some cases the capping layer includes the same elements asan anodically coloring material in one or more of the sublayers of thecounter electrode layer (e.g., the capping layer may include the sameelements that are present in the first sublayer, the second sublayer,etc.). In one example the capping layer is made of NiWO, where thecomposition of NiWO in the capping layer may be the same or differentfrom the composition of NiWO used elsewhere in the device, for examplein a first sublayer of a counter electrode layer. In another example,the capping layer may be made of NiWTaO, NiWSnO, NiWNbO, or anotheranodically coloring counter electrode material, where the composition ofthe capping layer may be the same or different from the composition ofthis material used in other portions of the device, for example in asecond sublayer of a counter electrode layer. Although the capping layermay be made of an anodically coloring material, in various embodimentsthis capping layer does not exhibit electrochromic behavior in afinished device. In certain embodiments, the capping layer may have anelectronic resistivity of between about 1 and 5×10¹⁰ Ohm-cm. Theintegrated deposition system 800 e also includes a station 856 fordepositing a layer of transparent conductive oxide (TCO). In someembodiments this layer may be indium-tin oxide (ITO).

Integrated depositions systems such as the ones shown in FIGS. 9A-9E mayalso have a TCO layer station, (not shown in 9A-9D) for depositing theTCO layer on the EC stack. Depending on the process demands, additionalstations can be added to the integrated deposition system, e.g.,stations for heating/annealing processes, cleaning processes, laserscribes, rotation processes, capping layers, defect mitigatinginsulating layers (DMILs), MTC, etc.

Although the foregoing embodiments have been described in some detail tofacilitate understanding, the described embodiments are to be consideredillustrative and not limiting. It will be apparent to one of ordinaryskill in the art that certain changes and modifications can be practicedwithin the scope of the appended claims.

1. (canceled)
 2. An apparatus for fabricating an electrochromic stack ona substrate, the apparatus comprising: a first electrochromic (EC) layerstation configured to deposit a first EC sublayer of an EC layer, thefirst EC sublayer comprising a cathodically coloring electrochromicmaterial; a first lithiation station configured to deposit metalliclithium from a lithium-containing source onto the EC layer; a second EClayer station configured to deposit a second EC sublayer of the EClayer, the second EC sublayer comprising a cathodically coloringelectrochromic material; a first counter electrode (CE) layer stationconfigured to deposit a CE layer or a first CE sublayer of the CE layer,the CE layer or the first CE sublayer comprising an anodically coloringelectrochromic material; and a controller being configured to cause thesubstrate to pass through stations comprised in the apparatus withoutbreaking vacuum and cause the apparatus to sequentially deposit layersof the electrochromic stack on the substrate.
 3. The apparatus of claim2, further comprising: a second lithiation station configured to depositmetallic lithium from a lithium-containing source onto the CE layer orthe first CE sublayer.
 4. The apparatus of claim 2, further comprising:a second CE layer station configured to deposit a second CE sublayer ofthe CE layer, wherein the first CE station is configured to deposit thefirst CE sublayer of the CE layer. 5.-14. (canceled)
 15. A method offabricating an electrochromic stack, the method comprising: depositing afirst electrochromic (EC) sublayer of an EC layer; depositing metalliclithium onto the first EC sublayer; depositing a second EC sublayer ofthe EC layer; and depositing a counter electrode (CE) layer.
 16. Themethod of claim 15, wherein the method includes only one operation ofdepositing metallic lithium. 17.-18. (canceled)
 19. The method of claim17, wherein the integrated deposition system includes only onelithiation station.
 20. The method of claim 15, wherein each EC sublayercomprises a cathodically coloring electrochromic material.
 21. Themethod of claim 20, wherein the cathodically coloring electrochromicmaterial comprises tungsten oxide.
 22. The method of claim 15, whereinone sublayer of the first and second EC sublayers is oxygen richcompared to the other sublayer of the first and second EC sublayer, theoxygen rich sublayer being proximal to the CE layer.
 23. The method ofclaim 15, wherein the first or second EC sublayer is a flash layer notthicker than 100 nm.
 24. The method of claim 15, wherein the CE layercomprises an anodically coloring electrochromic material.
 25. The methodof claim 15, the anodically coloring electrochromic material comprises anickel tungsten oxide composition.
 26. The method of claim 15, whereinthe CE layer comprises a first CE sublayer and a second CE sublayer.27.-31. (canceled)
 32. The method of claim 15, wherein depositing a CElayer comprises depositing the CE layer using a CE target.
 33. Themethod of claim 32, wherein the CE target is a ceramic target.
 34. Themethod of claim 33, wherein the ceramic target comprises a nickeltungsten oxide composition.
 35. The method of claim 33, wherein theceramic target comprises lithium.
 36. The method of claim 35, whereinthe ceramic target comprises a lithium nickel tungsten tantalum oxidecomposition.
 37. (canceled)
 38. The method of claim 15, furthercomprising heating the electrochromic stack.
 39. A method of fabricatingan electrochromic stack, the method comprising: depositing anelectrochromic (EC) layer of the electrochromic stack; depositingmetallic lithium onto the EC layer; and depositing a counter electrode(CE) layer of the electrochromic stack using a CE target. 40.-48.(canceled)